What does the Bible say about the Trinity?
The Father is the fountainhead of the Trinity, the Creator, the first cause. He is the primary thought, the concept of all that has been and will be created. Jesus said, "My Father has been working until now, and I have been working" (John 5:17).
The Son is the "Logos" or expression of God—the "only begotten" of the Father—and He Himself is God. Further, as God incarnate, He reveals the Father to us (John 14:9). The Son of God is both the agent of creation and mankind’s only Redeemer.
The Holy Spirit, the third Person of the Trinity, proceeds from the Father and is worshipped and glorified together with the Father and the Son. He inspired the Scriptures, empowers God’s people, and convicts the world "of sin, and of righteousness, and of judgment" (John 16:8).
All three Persons of the Godhead are eternal. The Father exists and has existed forever. With Him always existed His expression, the Son. Always the Father loved the Son, and the Son loved and served the Father. From that relationship of love exists the Spirit of God, who is eternal and has existed forever. The Father did not exist first, then later the Son, and still later the Spirit. They all three have existed from before there was anything that could begin_three distinct Persons all functioning as One. Upon the occasion of Jesus’ baptism, all three Persons in the Trinity were present and active. The Father spoke from heaven, the Son was fulfilling all righteousness, and the Spirit descended upon the Son like a dove (Matt. 3:16, 17).
The existence of the Trinity is a mystery that one day we will understand clearly. For now, we know that the Bible teaches it and Jesus revealed it, and the Christian church from the beginning has confessed and safeguarded this precious truth (I Cor. 12:4–6; 2 Cor. 13:14; Eph. 4:4–6; 2 Thess. 2:13, 14).