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.

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).