Although Natural Theology could posit God’s existence and HIS attributes, Trinity, however, belongs to revealed theology. Trinity is a unique nature of God, which can only be comprehended when God reveals HIS nature to man, else man cannot comprehend the unique nature of God.
Since our mind is limited to comprehend the doctrine of Trinity, this doctrine should be honestly and diligently studied. Trinity is denied by Jehovah’s Witnesses, Islam and the likes. Hence, Christians dialoguing with the proponents of other worldviews ought to justify and defend the doctrine of the blessed Trinity.
While striving to understand the nature of God from the Bible, especially when there is no explicit mention of the Trinity, all the passages referring to this particular theme ought to be recognized and systematically interpreted. Thus the doctrine of Trinity is an entailment of a diligent hermeneutical enterprise; an exercise in Systematic Theology.
FORMULATION OF THE DOCTRINE OF TRINITY
The word “Trinity” is not found in the Bible. However, the term “Trinity” describes a doctrine that is implicit in the Bible. But the doctrine of Trinity is based on the several explicit teachings found in the Bible.
The following statements form the core of the doctrine of Trinity:1
1. The Father is God.
2. The Son is God.
3. The Holy Spirit is God.
4. The Father is not the Son.
5. The Father is not the Holy Spirit.
6. The Son is not the Holy Spirit.
7. There is exactly one God.
EVIDENCE FROM THE BIBLE
Trinity is plausible only if the Bible asserts the following three aspects of the Godhead:
(1) The oneness of God.
(2) The three persons who are God.
(3) The three-in-oneness of God.
The Oneness of God is taught in the following passages of the Bible: Exodus 20:2-3, “I am the Lord your God, who brought you out of Egypt, out of the land of slavery. “You shall have no other gods before me” (Emphasis Mine). The Hebrew translation of “before me” means literally “to my face.” Deuteronomy 4:35 says, “You were shown these things so that you might know that the Lord is God; besides him there is no other” (Emphasis Mine). The Shema in Deuteronomy 6 says, “Hear, O Israel: The Lord our God, the Lord is one” (v4, Emphasis Mine).
Moreover, God has commanded HIS people to love HIM and no-one else (Deuteronomy 6:5) and fear and serve HIM and no-one else (Deuteronomy 6:13).
Verses revealing the oneness of God are not limited to the Old Testament. The New Testament also emphasizes the oneness of God (1 Corinthians 8: 4, 6; 1 Timothy 2:5-6; James 2:19).
The Bible teaches that there are three distinct persons in the Godhead with three sets of cognitive faculties.
The Father is God (John 6: 27; Galatians 1:1; 1 Corinthians 8:4, 6; 1 Timothy 2:5).
The Lord Jesus Christ’s deity is affirmed in the Bible (Isaiah 9:6-7; John 1:1, 20:28-29; Philippians 2: 5-11; Hebrews 1: 3a, 8; Titus 2:13; 2 Peter 1:1; Colossians 1:15-20, 2:9). Christ was placed on an equal footing with God (Matthew 28:19). Christ claimed to forgive sins (Mark 2: 8-10), for which HE was accused of blasphemy by the ardent Jews, for only God can forgive sins. Christ spoke of the angels as HIS angels (Matthew 13:41). He regarded the Kingdom of God (Matthew 12:28, 19:14, 24, 21:31, 43) and the elect of God as HIS own (Mark 13:20). Christ also claimed the power to judge the world (Matthew 25:31-33) and reign over it (Matthew 24:31; Mark 14:62). Significantly, Christ did not deny HIS deity before Caiaphas, “And the high priest answered and said to Him, “I put You under oath by the living God: Tell us if You are the Christ, the Son of God!” Jesus said to him, “It is as you said…” (Matthew 26:63-64, NKJV, Emphasis Mine). Last but not the least, Thomas addressed Christ as HIS God (John 20:28).
There are biblical references that identify the Holy Spirit as God (Psalm 139:7-10; Acts 5:3-4). The Holy Spirit is described as having the qualities of God and performing HIS works (John 3:8, 16:7-11; 1 Corinthians 3: 16-17, 6: 19-20, 12: 4-11). The Spirit is also placed on an equal footing with God (Matthew 28:19; 2 Corinthians 13:14; 1 Peter 1:2). Mark 3:29 states that blasphemy against the Spirit of God is an unforgivable sin.
The three-in-oneness of God is also taught in the Bible:
Matthew 28: 19-20 links the three persons of the Godhead and places them in equality. It is imperative to note that the word “name” is singular while describing the three persons, “…baptizing them in the name of the Father and of the Son and of the Holy Spirit…”
The Pauline benediction also places the three persons of the Godhead in unity and equality (2 Corinthians 13:14).
John’s gospel provides the strongest evidence of a coequal Trinity (1:33-34, 14:16, 26, 16:13-15, 20:21-22 cf. 1 John 4:2, 13-14).
The oneness of the Father and the Son (John 10:30, 14:6-11), the Son and the Spirit (Romans 8:9) and Father and the Spirit (1 Corinthians 2:11) is also taught in the Bible.
Although the Bible does not explicitly state the three-in-oneness of God, adequate data is found in the Bible (as mentioned above), which suggests the unity of the three persons of the Godhead.
TRINITY & THE LAW OF NON-CONTRADICTION
The doctrine of Trinity is not self contradictory, “Some attempt to argue against the Trinity by asserting that the concept is in violation of the law of non-contradiction. How can God, they ask, be both one and three at the same time? The law of non-contradiction asserts that something cannot be ‘a’ and ‘non-a’ at the same time and in the same sense. I do not think the Trinity violates this principle, however, since the doctrine maintains that God is one in a sense and three in a different sense. He is one in substance or essence but not one in person…”2
THE PLAUSIBILITY ARGUMENT
Dr. William Lane Craig argues for the plausibility of the Trinity from the perspective of love, “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 a result of God’s free will, not a result of His nature. It belongs to God’s very essence to love, but it does not belong to His essence 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. Moreover, contemporary. [sic] cosmology makes it plausible that created persons have not always existed. But God is eternally loving. So again created persons alone are insufficient to account for God’s being perfectly loving. 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.”3
1http://edwardfeser.blogspot.in/2010/02/trinity-and-mystery.html, last accessed 18th February 2017.
2http://crossexamined.org/the-trinity-defended/, last accessed 18th February 2017.
3http://www.reasonablefaith.org/a-formulation-and-defense-of-the-doctrine-of-the-trinity, last accessed 18th February 2017.
All Scripture references are from NIV, unless otherwise mentioned.