In order to test our theory that studying Systematic Theology will help us know God better, let’s take a look at the doctrine of the Trinity.
The word “Trinity” cannot be found in the Bible but is a concept that many other religions critique, debate, and deny. Should we simply take it out as a stumbling block to others or is the Trinity essential to the faith? Most people have only heard an occasional sermon that mentions the Trinity at any length, and rarely has the average church attender studied the Trinity at great depth. But a thorough systematic study of the entire Bible reveals that the doctrine of the Trinity rests on a rock-solid foundation. The doctrine of the Trinity emerges from a plain reading of the Bible and forms an essential element of the Christian faith. Systematic Theology helps us look at what the whole of Scripture says about the Trinity.
You would start in the Old Testament with hints like the plural pronouns:
Gen. 1:26, “Let Us make man in Our image after Our likeness” or Isaiah 6:8, “”Whom shall I send, and who will go for Us?” Both of these verses use the first person plural (Our and Us). [See also Gen 3:22, 11:7 and many other verses]
Next, you would look at the Shema Israel in Deut 6:4 which says, “Hear, O Israel: The Lord our God, the Lord is one.” Two Hebrew words could have been used for “one.” The first, libad, has the connotation of an isolated unit. The other word, ehad, implies the idea of uniqueness more than isolation—a complex unity. The word ehad is the same word used in Gen. 2:24 where the man and woman will become one flesh.
You would also look at potential implications from the “majestic plural or plural of majesty.” The plural word Elohim used for the name of God almost always takes a singular verb or adjective. This is known as the majestic plural or plural of majesty and it is debated whether this indicates anything special about the Trinity.
You wouldn’t stay in the Old Testament in order to understand the Trinity, but you would also want to look at the New Testament. Perhaps the clearest expression is with the baptism of Jesus in Matt. 3:16-17,
Matt. 3:16-17 “And after being baptized, Jesus went up immediately from the water; and behold, the heavens were opened, and he saw the Spirit of God descending as a dove, [and] coming upon Him, and behold, a voice out of the heavens, saying, “This is My beloved Son, in whom I am well-pleased.”
You would find other verses in the New Testament that prove the Trinity. The following represent only a few of the possibilities to consider:
1 Cor. 13:4-6 Now there are varieties of gifts, but the same Spirit. 5 And there are varieties of ministries, and the same Lord. And there are varieties of effects, but the same God who works all things in all [persons].
Notice how all three members of the Trinity receive mention. And again:
2 Cor. 13:14 The grace of the Lord Jesus Christ, and the love of God, and the fellowship of the Holy Spirit, be with you all.
And other places with similar theological implication because of the mention of all three members of the Trinity.
Gal. 4:6 And because you are sons, God has sent the Spirit of his Son into our hearts, crying, “Abba! Father!”
Eph. 4:4-6 [There is] one body and one Spirit, just as also you were called in one hope of your calling; one Lord, one faith, one baptism, one God and Father of all who is over all and through all and in all.
And somewhere in that systematic study you would demonstrate that Jesus is God through miracles, claims, actions, and verses like John 20:28.
John 20:28-30 Thomas answered him, “My Lord and my God!” Jesus said to him, “Have you believed because you have seen me? Blessed are those who have not seen and yet have believed.” Now Jesus did many other signs in the presence of the disciples, which are not written in this book.
Surely Jesus would have corrected Thomas had he not been claiming to be God. Instead Jesus accepted the worship and the statement, “My Lord and my God!”
Perhaps you would look at John 14:15, which says the Spirit is “another of the same kind of comforter” an “allos” and not a “heteros” comforter. This verse teaches both that the Holy Spirit is a separate member of the Trinity and also that the Holy Spirit is of the “allos” kind, which means the same kind, affirming the deity of the Spirit.
And of course you would look at Acts 5:3-4,
Acts 5:3-4 “But Peter said, “Ananias, why has Satan filled your heart to lie to the Holy Spirit and keep back part of the price of the land for yourself? “While it remained, was it not your own? And after it was sold, was it not in your own control? Why have you conceived this thing in your heart? You have not lied to men but to God.” This verse clearly equates the Holy Spirit with God.”
Finally, in 1 Cor. 3:16 we learn that the temple of God is the temple of the Holy Spirit:
1 Cor. 3:16 Do you not know that you are the temple of God and that the Spirit of God dwells in you?
You would not receive this type of information presented in this way from a sermon on a specific text, but through a systematic study, you would clearly see that our description of God as Trinity flows from Scripture to help us understand God. I hope you have already begun to conclude that systematic study of the Bible should supplement text-driven preaching.
Editor’s Note: This is the fourth article in the series “Why You Should Study Systematic Theology” by Thomas White, vice president for student services and communications at Southwestern.