My proof is the Bible itself.
It is clear that you reject the Bible when it does not agree with the doctrines of men that you were taught.
Spare me the hogwash.
John 1:14 English Standard Version (ESV)
14 And the Word became flesh and dwelt among us, and we have seen his glory, glory as of the only Son from the Father, full of grace and truth.
What was the WORD before it became flesh?
No hogwash, just scripture and common sense, answer the question?