There is one God, eternally existent in three persons: God the Father, God the Son and God the Holy Spirit.

Who, being in the form of God, thought it not robbery to be equal with God  (Philippians 2:6)

And Jesus, when he was baptized, went up straightway out of the water: and, lo, the heavens were opened unto him, and he saw the Spirit of God descending like a dove, and lighting upon him:

And lo a voice from heaven, saying, This is my beloved Son, in whom I am well pleased.
(Matthew 3:16-17)

Ye have heard how I said unto you, I go away, and come again unto you. If ye loved me, ye would rejoice, because I said, I go unto the Father: for my Father is greater than I.  (John 14:28)

I came forth from the Father, and am come into the world: again, I leave the world, and go to the Father. (John 16:28)

And the Word was made flesh, and dwelt among us, (and we beheld his glory, the glory as of the only begotten of the Father,) full of grace and truth.  (John 1:14)

In the beginning was the Word, and the Word was with God, and the Word was God.  (John 1:1)

No man hath seen God at any time, the only begotten Son, which is in the bosom of the Father, he hath declared him.  (John 1:18)

I and my Father are one.  (John 10:30)

But when the Comforter is come, whom I will send unto you from the Father, even the Spirit of truth, which proceedeth from the Father, he shall testify of me  (John 15:26)

But the Comforter, which is the Holy Ghost, whom the Father will send in my name, he shall teach you all things, and bring all things to your remembrance, whatsoever I have said unto you.  (John 14:26)

For there are three that bear record in heaven, the Father, the Word, and the Holy Ghost: and these three are one.  (1 John 5:7)