Jesus Christ taught us the Trinity . Not that there are three Gods but One God for three reasons, and three purposes
1Jo 5:7 For there are three that bear record in heaven, the Father, the Word, and the Holy Ghost: and these three are one.
Jhn 14:7 If ye had known me, ye should have known my Father also: and from henceforth ye know him, and have seen him.
Jhn 14:26 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.
Jhn 15:26 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: