Trinity simply means “triunity.” God is not a simple unity; there is plurality in his unity. The Trinity is one of the great mysteries of the Christian Faith. Unlike an antinomy or paradox, which is a logical contradiction, the Trinity goes beyond reason but not against reason. It is known only by divine revelation, so the Trinity is not the subject of natural theology but of revelation.

The Basis for the Trinity
While the word Trinity does not occur there, the concept is clearly taught in the Bible. The logic of the doctrine of the Trinity is simple. Two biblical truths are evident in Scripture, the logical conclusion of which is the Trinity:
1. There is one God.
2. There are three distinct persons who are God: Father, Son, and Holy Spirit.
One God : The central teaching of Judaism called the Shema proclaims: “Hear, 0 Israel: The LORD our God, the LORD is one” (Deut. 6:4). When Jesus was asked the question, “What is the greatest commandment?” he prefaced the answer by quoting the Shema (Mark 12:29). In spite of his strong teaching on the deity of Christ (cf. Col. 2:9), the apostle Paul said emphatically, “there is but one God, the Father, from whom all things came and for whom we live” (1 Cor. 8:6a). From beginning to end, the Scriptures speak of one God and label all other gods as false (Exod. 20:3; 1 Cor. 8:5-6).
The Bible also recognizes a plurality of persons in God. Although the doctrine of the Trinity is not as explicit in the Old Testament as the New Testament, nonetheless, there are passages where members of the Godhead are distinguished. At times they even speak to one another (see Ps. 110:1).

The Father Is God
Throughout Scripture God is said to be a Father. Jesus taught his disciples to pray, “Our Father in heaven” (Matt. 6:9). God is not only “our heavenly Father” (Matt. 6:32) but the “Father of our spirits” (Heb. 12:9). As God, he is the object of worship. Jesus told the woman of Samaria, “Yet a time is coming and has now come when the true worshippers will worship the Father in spirit and truth, for they are the kind of worshippers the Father seeks” (John 4:23). God is not only called “our Father” (Rom. 1:7) many times but also “the Father” (John 5:45; 6:27). He is also called “God and Father” (2 Cor. 1:3). Paul proclaimed that “there is but one God, the Father” (I Cor. 8:6). Additionally, God is referred to as the “Father of our Lord Jesus Christ” (Rom. 15:6). Indeed, the Father and the Son are often related by these very names in the same verse (Matt. 11:27; 1 John 2:22).
The Son Is God
The deity of Christ is treated [in a future article] in the section on attacks on the Trinity and more extensively in Baker’s Encyclopedia of Christian Apologetics in an article entitled Christ, Deity of. As a broad overview it should he noted that:
Jesus claimed to be Yahweh God. YHWH, translated in some versions Jehovah, was the special name of God revealed to Moses in Exodus 3:14, when God said, “I AM WHO I AM.” In John 8:58, Jesus declares: “Before Abraham was born, I am.” This statement claims not only existence before Abraham, but equality with the “I AM” of Exodus 3:14. The Jews around him clearly understood his meaning and picked up stones to kill him for blaspheming (see Mark 14:62; John 8:58; 10:31-33; 18:5-6). Jesus also said, “I am the first and the last (Rev. 2:8). Jesus took the glory of God. Isaiah wrote, “I am the LORD [Yahweh], that is my name! I will not give my glory to another; or my praise to idols” (42:8) and, “This is what the LORD [Yahweh] says . . . I am the first and I am the last; apart from me there is no God” (44:6). Likewise, Jesus prayed, “Father, glorify me in your presence with the glory I had with you before the world began” (John 17:5). But Yahweh had said he would not give his glory to another.
While the Old Testament forbids giving worship to anyone other than God (Exod. 20:1- 4; Deut. 5:6-9), Jesus accepted worship (Matt. 8:2; 14:33; 15:25; 20:20; 28:17; Mark 5:6). The disciples attributed to him titles the Old Testament reserved for God, such as, “the first and the last” (Rev. 1:17; 2:8; 22:13), “the true light” (John 1:9), “the “rock” or “stone” (1 Cor. 10:4; 1 Peter 2:6-8; cf. Ps. 18:2; 95:1), the “bridegroom” (Eph. 5:28-33; Rev. 21:2), “the chief Shepherd” (I Peter 5:4), and “the great shepherd” (Heb. 13:20). They attributed to Jesus the divine activities of creating (John 1:3; Col. 1:15-16), redeeming (Hosea 13:14; Ps. 130:7), forgiving (Acts 5:31; Col. 3:13; cf. Ps. 130:4; Jer: 31:34), and judging (John 5:27).
They used titles of deity for Jesus. Thomas declared: “My Lord and my God!” (John 20:28). Paul calls Jesus the one in whom “the fullness of deity dwells bodily” (Col. 2:9). In Titus, Jesus is called, “our great God and savior” (2:13), and the writer to the Hebrews says of him, “Thy throne, 0 God, is forever” (Heb. 1:8). Paul says that, before Christ existed as a human being, he existed as God (Phil. 2:5-8). Hebrews 1:3 says that Christ reflects God’s glory, bears the stamp of his nature, and upholds the universe. The prologue to John’s Gospel also minces no words, stating, “In the beginning was the Word, and the Word was with God, and the Word [Jesus] was God” (John 1:1).
Jesus claimed equality with God in other ways. He claimed the prerogatives of God. He claimed to be Judge of all (Matt. 25:31-46; John 5:27-30), but Joel quotes Yahweh as saying, “for there I will sit to judge all the nations on every side” (Joel 3:12). He said to a paralytic, “Son, your sins are forgiven” (Mark 2:5b). The scribes correctly responded, “Who can forgive sins but God alone?” (vs. 7b). Jesus claimed the power to raise and judge the dead, a power which only God possesses (John 5:21, 29). But the Old Testament clearly taught that only God was the giver of life (Deut. 32:39; 1 Sam. 2:6) and the one to raise the dead (Psa. 71:20).
Jesus claimed the honor due God, saying, “He who does not honor the Son does not honor the Father, who sent him” (John 5:23b). The Jews listening knew that no one should claim to be equal with God in this way and again they reached for stones (John 5:18). When asked at his Jewish trial, “Are you the Christ (Messiah), the Son of the Blessed One?” Jesus responded, “I am, and you will see the Son of Man sitting at the right hand of the Mighty One and coming on the clouds of heaven” (Mark 14:61b-62).
The Holy Spirit Is God
The same revelation from God that declares Christ to be the Son of God also mentions another member of the triunity of God called the Spirit of God, or Holy Spirit. He too is equally God with the Father and the Son, and he too is a distinct person.
The Holy Spirit is called “God” (Acts 5:3-4). He possesses the attributes of deity, such as omnipresence (cf. Ps. 139:7-12) and omniscience (1 Cor. 2:10, 11). He is associated with God the Father in creation (Gen. 1:2). He is involved with other members of the Godhead in the work of redemption (John 3:5-6; Rom. 8:9-17, 27; Titus 3:5-7). He is associated with other members of the Trinity under the “name” of God (Matt. 28:18-20). Finally, the Holy Spirit appears, along with the Father and Son, in New Testament benedictions (for example, 2 Cor. 13:14).
Not only does the Holy Spirit possess deity but he also has a differentiated personality. That he is a distinct person is clear in that Scripture refers to “him” with personal pronouns (John 14:26; 16:13). Second, he does things only persons can do, such as teach (John 14:26; 1 John 2:27), convict of sin (John 16:7-11), and be grieved by sin (Eph. 4:30). Finally, the Holy Spirit has intellect (I Cor. 2:10,11), will (1 Cor. 12:11), and feeling (Eph. 4:30).
That the three members of the Trinity are distinct persons is clear in that each is mentioned in distinction from the others. The Son prayed to the Father (cf. John 17). The Father spoke from heaven about the Son at his baptism (Matt. 3:15-17). Indeed, the Holy Spirit was present at the same time, revealing that they coexist. Further, the fact that they have separate titles (Father, Son, and Spirit) indicate they are not one person. Also, each member of the Trinity has special functions that help us to identify them. For example, the Father planned salvation (John 3:16; Eph. 1:4); the Son accomplished it on the cross (John 17:4; 19:30; Heb. 1:1-2) and at the resurrection (Rom. 4:25; 1 Cor. 15:1-6), and the Holy Spirit applies it to the lives of the believers (John 3:5; Eph. 4:30; Titus 3:5-7). The Son submits to the Father (1 Cor. 11:3; 15:28), and the Holy Spirit glorifies the Son (John 16:14).

A Philosophical Defense of the Trinity
The doctrine of the Trinity cannot be proven by human reason; it is only known because it is revealed by special revelation (in the Bible). However, just because it is beyond reason does not mean that it goes against reason. It is not irrational or contradictory, as many critics believe.
The Logic of the Trinity
The philosophical law of non-contradiction informs us that something cannot be both true and false at the same time and in the same sense. This is the fundamental law of all rational thought. And the doctrine of the Trinity does not violate it. This can be shown by stating first of all what the Trinity is not. The Trinity is not the belief that God is three persons and only one person at the same time and in the same sense. That would be a contradiction. Rather, it is the belief that there are three persons in one nature. This may be a mystery but it is not a contradiction. That is, it may go beyond reason’s ability to comprehend completely, but it does not go against reason’s ability to apprehend consistently.
Further, the Trinity is not the belief that there are three natures in one nature or three essences in one essence. That would be a contradiction. Rather, Christians affirm that there are three persons in one essence. This is not contradictory because it makes a distinction between person and essence. Or, to put it in terms of the law of non-contradiction, while God is one and many at the same time, he is not one and many in the same sense. He is one in the sense of his essence but many in the sense of his persons. So there is no violation of the law of non-contradiction in the doctrine of the Trinity.
A Model of the Trinity
By saying God has one essence and three persons it is meant that he has one “What” and three “Whos.” The three Whos (persons) each share the same What (essence). So God is a unity of essence with a plurality of persons. Each person is different, yet they share a common nature.
God is one in his substance. The unity is in his essence (what God is), and the plurality is in God’s persons (how he relates within himself). This plurality of relationships is both internal and external. Within the Trinity each member relates to the others in certain ways. These are somewhat analogous to human relationships. The Bible’s descriptions of Yahweh as Father and Jesus as Son says something of how the Son relates to the Father. Also, the Father sends the Spirit as a Messenger, and the Spirit is a Witness of the Son (John 14:26). These descriptions help us understand the functions within the unity of the Godhead. Each is fully God, and each has his own work and interrelational theme with the other two. But it is vital to remember that the three share the same essence, so that they unify as one Being.

Some Illustrations of the Trinity
No analogy of the Trinity is perfect, but some are better than others. First, some bad illustrations should be repudiated. The Trinity is not like a chain with three links. For these are three separate and separable parts. But God is neither separated nor separable. Neither is God like the same actor playing three different parts in a play. For God is simultaneously three persons, not one person playing three successive roles. Nor is God like the three states of water: solid, liquid, and gaseous. For normally water is not in all three of these states at the same time, but God is always three persons at the same time. Unlike other bad analogies, this one does not imply tritheism. However, it does reflect another heresy known as modalism.
Most erroneous illustration of the Trinity tend to support the charge that trinitarianism is really tritheism, since they contain separable parts. The more helpful analogies retain the unity of God while they show a simultaneous plurality. There are several that fit this description.
A Mathematical Illustration
One aspect of the problem can be expressed in mathematical terms. Critics make a point of computing the mathematical impossibility of believing there is a Father, Son and Holy Spirit in the Godhead, without holding that there are three gods. Does not 1 + 1 + 1 = 3? It certainly does if you add them, but Christians insist that the triunity of God is more like 1 x I x 1 = 1. God is triune, not triplex. His one essence has multiple centers of personhood. Thus, there is no more mathematical problem in conceiving the Trinity than there is in understanding 1 cubed (13).
A Geometric Illustration
Perhaps the most widely used illustration of the Trinity is the triangle. One triangle has three corners, which are inseparable from, and simultaneous to, one another. In this sense it is a good illustration of the Trinity. Of course, the triangle is finite and God is infinite, so it is not an imperfect illustration.
Another aspect of the Godhead is that Christ is one person (shown as one corner of the triangle), yet he has two natures, a divine nature and a human nature. Some show this aspect graphically by symbolizing Christ’s divinity by the corner of the triangle and using another geometric figure, a circle for instance, to illustrate the human nature. At the point of the person of Jesus Christ, the circle is welded onto the triangle, human nature touching, but not mixed with, divine. Human and divine natures exist side-by-side without confusion in the Son. His two natures are conjoined in one person. Or, in Christ there are two Whats and one Who, whereas, in God there are three Whos and one What.
A Moral Illustration
Augustine suggested an illustration of how God is both three and one at the same time. The Bible informs us that “God is love” (1 John 4:16). Love involves a lover, a beloved, and a spirit of love between lover and loved. The Father might be likened to the Lover; the Son to the One loved, and the Holy Spirit is the Spirit of love. Yet love does not exist unless these three are united as one. This illustration has the advantage of being personal, since it involves love, a characteristic that flows only from persons.
An Anthropological Illustration
Since humankind is made in the image of God (Gen. 1:27), it would seem reasonable that men and women bear some snapshot of the Trinity within their being. One that causes more problems than it solves is to visualize the human being as a “trichotomy” of body, soul, and spirit. Whether the trichotomist position is accurate, this is not a helpful illustration. Body and soul are not an indivisible unity. They can be (and are) separated at death (cf. 2 Cor. 5:8; Phil. 1:23; Rev. 6:9). The nature and persons of the Trinity cannot be separated.
A better illustration based in human nature is the relation between the human mind, to its ideas, and the expression of these ideas in words. There is obviously a unity among all three of these without there being an identity. In this sense, they illustrate the Trinity.

An Islamic Illustration of Plurality in God
When talking with Muslims, the best illustration of a plurality is the relation between the Islamic conception of the Qur’an and God. Yusuf K. Ibish in an article entitled, “The Muslim Lives by the Qur’an,” cited by Charis Waddy, The Muslim Mind, described it this way: The Qur’an “is an expression of Divine Will. If you want to compare it with anything in Christianity, you must compare it with Christ himself. Christ was the expres¬sion of the Divine among men, the revelation of the Divine Will. That is what the Qur’an is.”
Orthodox Muslims believe the Qur’an is eternal and uncreated. It is not the same as God but is an expression of God’s mind as imperishable as God himself. Surely, there is here a plurality within unity, something that is other than God but is nonetheless one with God in essential characteristics.
Attacks on the Trinity
The Trinity is at the heart of orthodox Christianity. But many critics—Jews and Muslims in particular—contend that it is incoherent and contradictory. Orthodox Christians insist that the teaching that God is one in essence but three in personhood is complex, but not contradictory.
The central issue is the deity of Christ, a doctrine inseparable from the Trinity. If one accepts the biblical teaching about the deity of Christ, then a plurality in the Godhead has been acknowledged. Conversely, if the doctrine of the Trinity is received, the deity of Christ is part of the package. Of course, strict monotheists, such as Muslims and Orthodox Jews, reject both the deity of Christ and the Trinity as a denial of the absolute unity of God.
Muslim Misunderstanding
Obstacles in the Muslim mind hinder acceptance of the triunity of God. Some are philosophical; some biblical. Islamic scholars often engage in an arbitrary and selective use of the biblical texts as it suits their purposes. However, even the texts they pronounce “authentic” are twisted or misinterpreted to support their teachings. Christ as “begotten” of God
Perhaps no Christian concept draws so violent a reaction among Muslims than that of Jesus as the “only begotten Son of God.” This raises red flags immediately, because Muslims understand the words in a grossly anthropomorphic way. Evangelical Christians likewise would be offended to hear what Muslims think they hear in this term. Clearing away this misunderstanding is necessary
The King James Version Bible refers to Christ as the “only begotten” Son of God (John 1:18; cf. 3:16). However, Muslim scholars often misconstrue this in a fleshly, carnal sense of someone who literally begets children. To “beget” implies the physical act of sexual intercourse. This they believe, and Christians agree, is absurd. God is a Spirit with no body. As the Islamic scholar Anis Shorrosh contents, “He [God] does not beget because begetting is an animal act. It belongs to the lower animal act of sex. We do not attribute such act to God” (Shorrosh, 254). But only a few cults, notably the Latter-Day Saints (Mormons) have a teaching that approaches this view of “begetting.”
Further, to the Islamic mind, begetting is “creating.” “God cannot create another God.... He cannot create another uncreated” (ibid., 259). Once again, Christians would agree fully. The foregoing statements reveal the degree to which the biblical concept of Christ’s Sonship is misunderstood by Muslim scholars. For no orthodox Christian equates the King James Version translation of “begat” with “made” or “create.” Arianism taught that and was strenuously fought wherever it has appeared in church history. Its primary adherents today belong to another cult, Jehovah’s Witnesses. No wonder ‘Abdu ‘L-Ahad Dawud concludes that from a “Muslim point of belief the Christian dogma concerning the eternal birth or generation of the Son is bIasphemy” (205).
New, more accurate English translations have been more careful to say in English what was originally meant in Greek. Only begotten does not refer to any physical generation but to a special relationship between the Son and the Father. It means a unique relationship, or could be translated, as the New International Version, “one and only Son.” It does not imply creation by the Father or any other sort of generation. Just as an earthly father and son have a special filial relationship, so the eternal Father and his eternal Son are uniquely and intimately working in concert with one another. It does not refer to physical generation but to an eternal procession from the Father. Just as for Muslims the Word of God (Qur’an) is not identical to God but eternally proceeds from him, even so for Christians, Christ, God’s “Word” (sura 4:171) eternally proceeds from him. Words like generation and procession are used of Christ in a filial and relational sense, not in a carnal and physi-cal sense.
Some Muslim scholars confuse Christ’s Sonship with his virgin birth. Michael Nazir-Ali noted that “in the Muslim mind the generation of the Son often means his birth of the Virgin Mary” (Nazir-Ali, 29). As Shorrosh notes, many Muslims believe Christians have made Mary a goddess, Jesus her son, and God the Father her husband (114). With such a carnal misrepresentation of a spiritual reality, there is little wonder Muslims reject the Christian concept of eternal Father and Son.
Islamic misunderstanding of the Trinity is encouraged by the misunderstanding of Muhammad, who said, “0 Jesus, son of Mary! didst thou say unto mankind: Take me and my mother for two gods beside Allah?” (sura 5:119). Hundreds of years before Muhammad Christians condemned such a gross misunderstanding of the sonship of Christ. The Christian writer Lactantius (240-320), writing in about 306, said, “He who hears the words ‘Son of God’ spoken must not conceive in his mind such great wickedness as to fancy that God procreated through marriage and union with any female—a thing which is not done except by an animal possessed of a body and subject to death.” Furthermore, “since God is alone, with whom could he unite? or [sic], since He was of such great might as to be able to accomplish whatever He wished, He certainly had no need of the comradeship of another for purpose of creating” (Pfander, 164).
Distortion of John 1:1
If rejection of the eternal Sonship of Christ is based on a serious misunderstanding of the Christian concept of Christ as God’s Son, another text proclaiming Christ’s deity is often distorted: “In the beginning was the Word, and the Word was with God, and the Word was God” (John 1:1). Without textual support from even one of the 5300 plus Greek manuscripts, Muslims render the last phrase, “and the Word was God’s.” Dawud declares, without any warrant, “the Greek form of the genitive case ‘Theou,’ i.e., ‘God’s’ was corrupted into ‘Theos’; that is, ‘God,’ in the nominative form of the name!” (16-17).
This translation is not only arbitrary, but it is contrary to the rest of the message of John’s Gospel where the claims that Christ is God are made multiple times (cf. John 8:58; 10:30; 12:41; John 20:28).
Misconstruing Thomas’s confession
When Jesus challenged Thomas to believe after seeing him in his physical resurrection body, Thomas confessed Jesus’ deity, declaring, “My Lord and My God” (John 20:28). Many Muslim writers diminish this proclamation of Christ’s deity by reducing it to an ejaculatory exclamation, “My God!” Deedat declares, “What? He was calling Jesus his Lord and his God? No. This is an exclamation people call out. . . . This is a particular expression” (Shorrosh, 278).
Deedat’s alternative reading is not viable. First, in an obvious reference to the content of Thomas’s confession of Jesus as “my Lord and my God,” Jesus blessed him for what he had correctly “seen” and “believed” (John 20:29). Thomas’s confession of Christ’s deity comes in the context of a miraculous appearance by the risen Christ, not to mention at the climax of the post-resurrection ministry, when Jesus’ disciples were gaining increasing belief in Christ, based on his miraculous signs (cf. John 2:11; 12:37). Thomas’s confession of Christ’s deity fits with the stated theme of the Gospel of John “that you may believe that Jesus is the Christ, the Son of God, and that believing you may have life in his Name” (John 20:31). Even putting all this aside, Thomas was a devout Jew who revered the name of God. He simply would not have used God’s name in so profane an ejaculation. No doubt there was an amazed note in Thomas’s voice as he pronounced Christ’s deity, but to reduce it to an emotional ejaculation is to claim that Jesus blessed Thomas for breaking the commandment against using God’s name in vain.
David’s Son and David’s Lord
In Matthew 22:43, citing Psalm 110, Jesus said, “How is it then that David, speaking by the Spirit, calls him ‘Lord’ [Messiah]?” According to Dawud, “By his expression that the ‘Lord,’ or the ‘Adon,’ could not be a son of David, Jesus excludes himself from that title” (89).
However, a careful look at the context shows that Jesus is saying just the opposite. Jesus stumped his skeptical Jewish questioners by presenting them with a dilemma that blew their own neat calculations about the Messiah out of the sky. How could David call the Messiah “Lord” (as he did in Ps. 110:1), when the Scriptures also say the Messiah would be the “Son of David” (which they do in 2 Sam. 7:12f.)? The only answer is that the Mes¬siah must be both a man (David’s son or offspring) and God (David’s Lord.) Jesus is claim¬ing to be both God and human. The Islamic mind should have no more difficulty under¬standing how Jesus can unite in one person both divine and human natures than their own belief that human beings combine both spirit and flesh, the enduring and the transient in one person (sura 89:27-30; cf. 3:185). Even according to Muslim belief, whatever Almighty God, the Creator and Ruler of all things, wills in his infinite wisdom he is also able to ac-complish for “He is the irresistible” (sura 6:61).
God only good
Many Islamic scholars claim that Jesus denied being God when he rebuked the rich young ruler, saying, “Why do you call me good? No one is good—except God alone” (Mark 10:18). A careful look at this text in its context reveals that Jesus was not denying his deity. He was rather warning the young man to consider the implications of his careless appellation. Jesus does not say, “I am not God, as you claim” or “I am not good.” Indeed, both the Bible and Qur’an teach that Jesus is sinless (cf. John 8:46; Heb. 4:14). Rather, Jesus challenged him to examine what he was really saying when he called Jesus “Good Master.” In essence, Jesus was saying, “Do you realize what you are saying when you call Me ‘Good Master’? Only God is good. Are you calling me God?” The fact that the young ruler refused to do what Jesus said, proves that he did not really consider Jesus his Master. But nowhere did Jesus deny that he was either the Master or God of the rich young ruler. Indeed, elsewhere Jesus freely claimed to be both Lord and Master of all (Matt. 7:21- 27; 28:18; John 12:40).
The greater Father
Jesus’ assertion that “My Father is greater than I” (John 14:28) is also misunderstood by Muslims. It is taken out of its actual context to mean that the Father is greater in nature, but Jesus meant only that the Father is greater in office. This is evident from the fact that in this same Gospel (of John) Jesus claimed to be the “I Am” or Yahweh of the Old Testament (Exod. 3:14). He also claimed to be “equal with God” (John 10:30, 33). In addition, he received worship on numerous occasions (John 9:38; cf. Matt. 2:11; 8:2; 9:18; 14:33; 15:25; 28:9, 17; Luke 24:52). He also said, “He who does not honor the Son does not honor the Father who sent him” (John 5:23).
Further, when Jesus spoke of the Father being “greater” it was in the context of his “going to the Father” (John 14:28). Only a few chapters later Jesus speaks to the Father, saying, “I have completed the work you gave me to do” (John 17:4). But this functional difference of his role as Son in the very next verse reveals that it was not to be used to diminish the fact that Jesus was equal to the Father in nature and glory. For Jesus said, “And now, Father, glorify me in your presence with the glory which I had with you before the world began” (John 17:5).

Misunderstood Philosophical Concepts
Islamic scholars also offer philosophical objections to the doctrine of the Trinity. These too must be cleared away before they will be able to understand the biblical teaching about a plurality of persons within the unity of God.
Emphasis on the Oneness of God is fundamental to Islam. One Muslim scholar said, “In fact, Islam, like other religions before it in their original clarity and purity, is nothing other than the declaration of the Unity of God, and its message is a call to testify to this Unity” (Mahud, 20). Another author adds, “The Unity of Allah is the distinguishing characteristic of Islam. This is the purest form of monotheism, i.e., the worship of Allah Who was neither begotten nor beget nor had any associates with Him in his Godhead. Islam teaches this in the most unequivocal terms” (Ajijola, 55).
Because of this uncompromising emphasis on God’s absolute unity, in Islam the great¬est of all sins is the sin of shirk, or assigning partners to God. The Qur’an sternly declares “God forgiveth not (The sin of) joining other gods With Him; but He forgiveth Whom He pleaseth other sins Than this: one who joins Other gods with God, Hath strayed far, far away (From the Right)” (sura 4:116). However, this misunderstands the unity of God.
The Trinity and heresy
There are two primary heresies from which the Trinity is to be distinguished: modalism and tritheism. The heresy of modalism, also called Sabellianism, denies there are three distinct eternal persons in the Godhead. It believes that the so-called “persons” of the Trinity are modes of God substance, not distinct persons. Like water with its three states (liquid, solid, and gaseous), the Trinity is said to be only three different modes of the same essence. Unlike modalists, trinitarians believe there are three distinct persons (not just modes) in the one substance of God.
Both Islam and Christianity proclaim that God is one in essence. What is in dispute is whether there can be any plurality of persons in this unity of nature. The inadequacies in the Muslims’ view of God arise in part out of their misunderstanding of Christian monotheism. Many Muslims misconstrue the Christian view of God as tritheism rather than as monotheism. The opposite error of tritheism affirms that there are three separate gods. Few, if any, Christian theologians or philosophers have held this view, but it often has been attributed to trinitarians. Unlike tritheists, trinitarians do not affirm a god with three different substances; they confess that God is three distinct persons in one substance.
The Bible declares emphatically: “The LORD our God, the LORD is one” (Deut. 6:4). Both Jesus (Mark 12:29) and the apostles repeat this formula in the New Testament (1 Cor. 8:4, 6). And early Christian creeds speak of Christ being one in “substance” or “essence” with God. The Athanasian Creed reads: “We worship one God in Trinity, and Trinity in Unity; Neither confounding the Persons; nor divining the Substance (Essence).” So Chris¬tianity is a form of monotheism, believing in one and only one God.
The Trinity and complexity
Many Muslims complain that the Christian concept of the Trinity is too complex. They forget, however, that truth is not always simple. As C. S. Lewis aptly puts it, “If Christianity was something we were making up, of course we could make it easier. But it is not. We cannot compete, in simplicity, with people who are inventing religions. How could we? We are dealing with fact. Of course anyone can be simple if he has no facts to bother about” (Lewis, 145).
The fact confronting Christians which led to their formulating this complex truth was, of course, the claims and credentials of Jesus of Nazareth to be God. This led them of necessity to posit a plurality within deity and thus the doctrine of the Trinity, since this Jesus was not the same as the one whom he addressed as Father. So Christians believe and Muslims deny that there are three persons in this one God. At this point the problem gets philosophical.
The Neoplatonic concept of unity
At the heart of the Muslim inability to understand the Trinity is the neoplatonic concept of oneness. The second-century A.D. philosopher Plotinus, who heavily influenced the thinking of the middle ages, viewed God (the Ultimate) as the One, an absolute unity in which is no multiplicity at all. This One was so absolutely simple that it could not even know itself, since self-knowledge implies a distinction between knower and known. It was not until it emanated one level down, in the Nous or Mind, that it could reflect back on itself and therefore know itself. For Plotinus, the One itself was beyond knowing, beyond consciousness, and even beyond being. It was so undividedly simple that in itself it had no mind, thoughts, personality, or consciousness. It was void of everything, even being. Thus, it could not be known, except by its effects which, however; did not resemble itself (Plotinus, 1.6; 3.8-9; 5.1, 8; 6.8, 18).
It is not difficult to see strong similarities between the Plotinian and Muslim views of God. Nor is it hard to see the difficulty with this view. It preserves a rigid unity in God at the expense of real personality. It clings to a rigid simplicity by sacrificing relationship. It leaves us with an empty and barren concept of deity. By reducing God to a bare unity, they are left with a barren unity. As Joseph Ratsinger insightfully noted,
The unrelated, unrelatable, absolutely one could not be a person. There is no such thing as a person in the categorical singular. This is already apparent in the words in which the concept of person grew up; the Greek word “prosopon” means literally “(a) look towards”; with the prefix ‘pros’ (toward). It includes the notion of relatedness as an integral part of itself. . . . To this extent the over-stepping of the singular is implicit in the concept of person. [Ratsinger, 128-29]

CONFUSION REGARDING THE TRINITY
Confusing unity with singularity
The Muslim God has unity and singularity. But these are not the same. It is possible to have unity without singularity. For there could be plurality within the unity. Indeed, the Trinity is precisely a plurality of persons within the unity of one essence. Human analogies help to illustrate the point in a superficial way. My mind, my thoughts, and my words have a unity, but they are not a singularity, since they are all different. Likewise, Christ can express the same nature as God without being the same person as the Father.
In this connection, Muslim monotheism sacrifices plurality in an attempt to avoid duality. In avoiding the extreme of admitting any partners to God, Islam goes to the other extreme and denies any personal plurality in God. But, as Joseph Ratsinger observed, “belief in the Trinity, which recognizes the plurality in the unity of God, is the only way to the final elimination of dualism as a means of expanding plurality alongside unity; only through this belief is the positive validation of plurality given a definite base. God stands above singular and plural. He bursts both categories” (Ratsinger, 128).
Confusing person (who) and nature (what)
That Christ “bursts the categories” explains why Christian and non-Christian alike have struggled to understand the two natures of Christ. One of the better explanations of what Christians believe, though it doesn’t go far toward explaining it, is found in one of the sixteenth-century Reformation statements of faith, the Belgic Confession, chapter 19:
We believe that by this conception [of two natures], the person of the Son is inseparably united and connected with the human nature; so that there are not two Sons of God, nor two persons, but two natures united in one single person; yet each nature retains its own distinct properties. As, then, the divine nature has always remained uncreated, without beginning of days or end of life, filling heaven and earth, so also has the human nature not lost its properties but remained a creature, having beginning of days, being a finite nature, and retaining all the properties of a real body. ... But these two natures are so closely united in one person that they were not separated even by his death. . . . Wherefore we confess that he is very God and very man: very God by His power to conquer death; and very man that He might die for us according to the infirmity of His flesh.
Orthodox Christianity does not believe Jesus Christ was like a milkshake, the two natures blended together in an indistinguishable mass. Neither do Christians believe Jesus had a schizophrenically split identity in which divine and human natures were so distinct they would have had to call one another long-distance. These views and other equally wrong ideas have muddied Christian theology throughout its history. A popular modern theory, which misses the whole point of Philippians 2 and the reason God had to take on a human nature states that Jesus emptied himself of all his divine attributes of power and authority and kept only his moral perfection. So how is it conceivable? The orthodox view is that God the Son took off nothing of his godhood, but rather added to it the human nature. He accepted limitations. As a human being, Jesus had to grow up and learn. He felt want and sorrow and there were things the human nature of Jesus did not know, such as the date of his return (Matt. 24:36).
One theologian, Charles Hodge, wondered if God did not draw the clearest analogy of the two natures in the design of Israel’s temple at Jerusalem. The inner court where the daily work of worship and the sacrifice happened was the court of Israel or the holy place. But within this space was another room that represented the presence of God in the midst of his people. This central room, the “holy of holies” was only entered by the high priest once a year. A curtain separated the two sections of the sanctuary so that the room was hidden. But symbolically it empowered the priests in their daily life in temple worship. The two were unmixed but united and inseparable.
The orthodox view of the two natures of Christ is that one person is both God and human. The two natures commune intimately but do not overlap. Christ possesses two natures united. Hence, when Jesus died on the cross for our sin he died as the God-man. It is not going too far, said John Calvin, to say that at the moment Jesus was hanging on the cross his power as Creator God was holding together the hill on which the cross stood. Unless Jesus is God and human he cannot reconcile God and humanity. But the Bible says clearly, “there is one God and one mediator between God and men, the man Christ Jesus” (1 Tim. 2:5).
Since Christ is one Who (person) with two What’s (natures), whenever one question is asked about him it must be separated into two questions, one applying to each nature. For example, did he get tired? As God, no; as human, yes. Did Christ get hungry? In his divine nature, no; in his human nature, yes. Did Christ die? In his human nature, he did die. His divine nature is eternally alive. He died as the God-man, but his Godness did not die.
When this same logic is applied to other theological questions raised by Muslims it yields the same kind of answer. Did Jesus know everything? As God he did, since God is omniscient. But as man Jesus did not know the time of his second coming (Matt. 24:36), and as a child he “increased in wisdom” (Luke 2:52).
Could Jesus sin? The answer is the same: as God, no; as man yes (but he didn’t). God cannot sin. For example, the Bible says it is impossible for God to lie” (Heb. 6:18; cf. Titus 1:2). Yet Jesus was “in all points tempted as we are, yet without sin” (Heb. 4:15). While he never sinned (cf. 2 Cor. 5:21; 1 Peter 1:19; 1 John 3:3), he was really tempted and it was possible for him to sin. 0therwise, his temptation would have been a charade. Jesus possessed the power of free choice which means that when he chose not to sin it was a meaningful choice. He could have done otherwise.
Dividing every question of Christ into two and referring them to each nature unlocks a lot of theological puzzles that otherwise remain shrouded in ambiguity. And it makes it possible to avoid logical contradictions which are urged upon Christians by Muslims and by other nonbelievers. Conclusion
The doctrine of the Trinity is one of the great mysteries of the Christian Faith. That is, it transcends reason without being contrary to reason. It is not known by reason but only by special revelation. God is one in essence but three in persons. He is a plurality within unity. God is a triunity, not a rigid singularity.
Once those conceptions are understood, many of the barriers that separate even such radical monotheists as Orthodox Jews and Muslims fall.

God is by definition the greatest conceivable being. As the greatest conceivable being, God must be perfect. Now a perfect being must be a loving being. For love is a moral perfection; it is better for a person to be loving rather than unloving. God therefore must be a perfectly loving being. Now it is of the very nature of love to give oneself away. Love reaches out to another person rather than centering wholly in oneself. So if God is perfectly loving by his very nature, he must be giving himself in love to another. But who is that other? It cannot be any created person, since creation is the result of God’s free will, not the result of his nature. It belongs to God’s very essence to love, but it does not belong to it to create. So we can imagine a possible world in which God is perfectly loving and yet no created persons exist. So created persons cannot sufficiently explain whom God loves… It therefore follows that the other to whom God’s love is necessarily directed must be internal to God himself. In other words, God is not a single, isolated person, as Unitarian forms of theism like Islam hold; rather, God is a plurality of persons, as the Christian doctrine of the Trinity affirms. On the Unitarian view God is a person who does not give himself away essentially in love for another; he is focused essentially only on himself. Hence, he cannot be the most perfect being. But on the Christian view, god is a triad of persons in eternal, self-giving love relationships. Thus, since God is essentially loving, the doctrine of the Trinity is more plausible than any Unitarian doctrine of God.[66] -
J.P. Moreland and William Lane Craig