The concept of a triune God, or the Trinity, is a man made concept which is not true. Why?
Mark 10:18
18 And Jesus said unto him, Why callest thou me good? there
is none good but one, that is, God.
Mark 12:29
29 And Jesus answered him, The first of all the commandments
is, Hear, O Israel; The Lord our God is one Lord:
Mark 12:32
32 And the scribe said unto him, Well, Master, thou hast said
the truth: for there is one God; and there is none other but he:
John 7:16
16 Jesus answered them, and said, My doctrine is not mine, but his that
sent me.
There is no harm in believing in the union of JEHOVAH and JESUS and The Holy Spirit, as long as you realize JESUS is His own individual self. Other wise you end up saying JESUS is really GOD, and in that sense you say JESUS does not exist, and that will damn your soul come judgment time.
To put this on a more personal level, with you, how would you like it if someone said to you that you don't even exist, but you are your dad, and your dad is you, and you are only a reincarnation of your dad. But how would that be possible if your dad is still alive. And that is the case with JESUS CHRIST, He is alive and also His FATHER JEHOVAH is alive, and JEHOVAH is the one who creates all life. Life forms like you, and JESUS, and me.
Matthew 10:33
33 But whosoever shall deny me before men, him will I also deny before my Father which is in heaven.