Possibly Melchizedek “ Without father, without mother, without descent, having neither beginning of days, nor end of life”. Who could that be since no man has seen God the Father?
Also here in Daniel
“ Then Nebuchadnezzar the king was astonished, and rose up in haste, and spake, and said unto his counsellors, Did not we cast three men bound into the midst of the fire? They answered and said unto the king, True, O king.
He answered and said, Lo, I see four men loose, walking in the midst of the fire, and they have no hurt; and the form of the fourth is like the Son of God”
Old Testament evidence of the Trinity
In psalm 110 David said:
The Lord said unto my Lord, Sit thou at my right hand, until I make thine enemies thy footstool.
The Holy Ghost as part of the Godhead is described in 1 John 5-7
""For there are three that bear record in heaven, the Father, the Word, and the Holy Ghost: and these three are one."
Romans 10 9
“ That if thou shalt confess with thy mouth the Lord Jesus, and shalt believe in thine heart that God hath raised him from the dead, thou shalt be saved.”.
God the Son died on the cross and God the Father raised him from the dead.
Also in Mathew 11 Jesus said
“All things are delivered unto me of my Father: and no man knoweth the Son, but the Father; neither knoweth any man the Father, save the Son“