At this point in my life, I cannot find substance or proof in the Bible to validate using the term trinity, for these reasons:
1) It is not a term used in the bible.
2) There is no reference in the bible of God asking us to re-explain his diety and existence.
3) There is no prophecy or reference to the Holy spirit being a human.
4) There is specific reference to God being a spirit and not having flesh and bones. Only in the son-ship is there a bodily form specified, and that as a heavenly conception.
5) In the birth of Jesus there was a baby that grew up into a man, and that defies reference to an eternal flesh and blood person. he would have had to be already grown up in heaven and then reborn into the flesh as a baby.
6) I feel safer not using Tertullian based trinity or any other human concept or doctrine for the simple reason they are man-made, and not authenticated by the scripture.
7) Isaiah (old testament prophet) amply allows for the Christ child, and the savior to come, without altering or changing the eternal oneness of God. All of Isaiah is filled with Gods Oneship. WE might be bringing a curse by trying to make that oneness into three distinct persons with distinct humanness, separate minds, separate goals, etc.
8) The purpose of God was fulfilled in a father-son-holy spirit manifestation. It was his method to reach mankind and to re-unite us to himself. It was not to separate or to present separate god-ships, as that would have violated who he was.
conclusion: I can believe in the God of the Bible without using a man made concept of trinity. I understand for many that this is a stumbling-block, as they have been mainstreamed into orthodoxy, Catholic, Trinity, and other religious tradition.
Many world-wide believers have remained true to the Bible and its teachings. If you do so, however, you won't be using the word trinity, or terms like "co-equal persons" because the aren't in Gods book of life. God is a spirit and they that worship him must worship him in spirit and in truth. there's nothing hard or complicated about that. When it says Great is the mystery of Godliness, God was manifest in the flesh, he didn't say "in three fleshs" , but only one flesh.. how he otherwise manifested himself in history is best left as it is.
Several times we are told, "but ye brethren may understand the mystery, are not in darkness, etc.:" Rightly dividing the word of truth and loving the truth is important. We must not add any man made doctrines, of which there are many. Trinity doctrine was created and written and approved by supposed converted Roman scholars who were engaged in taking over the fledgling but already established church and this doctrine was incorporated and has dominated many organizations without authenticity, except by church propagation of councils, and orders and as a separate doctrine than of the true bible. HOW can it be believed or taught as truth, if it has been (supposedly) added to the faith as a valid teaching, yet authored not by God, but by man? Why would anyone WANT to add to the word?
IF God DOES have a specific form or shape, it obviously is not a human body, as he is God, and he specifically says he does not have flesh and bones. to think so even is silly. to think that of the spirit is just as silly. perhaps it is just as humans with human minds we think we have to give God a Body that we can identify. well, could it just be, that he did give us one we could identify and trust in and hope for ? the person of Jesus in Salvation. WE will know the rest of it as soon as we have our glorified bodies and are over there in the supernatural realm, right? according to Isaiah 9:6, Jesus IS the mighty God come in the flesh.
