Who is God in the Old Testament? (Trinity)

I had always thought the Entity of the Trinity that appears in the Old Testament was God the Father. However, upon re-reading several passages, I am beginning to think it might be Jesus Christ. The Referenced Verses, John 6:46 and John 14:6 - Which say 'Not that anyone has seen the father, except he who is from God (Jesus Christ)' and 'Nobody can come to the father except through me(Jesus Christ)' (ESV) From these Statements from Christ, I am inclined to believe the 'LORD' in the old testament was actually Jesus Christ, and not the Father - as I've always assumed. If Nobody has ever come to the Father, or seen the Father except through Christ - Moses must not have been interacting with the Father, Right? Please let me know what you think of this. Did the Old Testament ever make specific reference that God was God the Father? Thank you