When you say "God" here ^^, do you mean "Jesus"?
Jesus is the second person in the Godhead. The concept of the Trinity existed in ancient Jewish culture,even though it wasn't in as much detail as in the New Testament. The Bible is there to make up wise unto salvation. It's not there to mention every detail there is on everything. It can't, it's a limited book. Is Jesus Christ The Angel of The Lord? – Finding Christ In The Old Testament
Who did Moses see in the burning bush? It was Jesus Christ.
Is Jesus The Angel of The Lord? Does Jesus Christ Appear In The Old Testament? What Was Jesus Doing During Old Testament Times?- A Biblical Study
Search the scriptures; for in them ye think ye have eternal life: and they are they which testify of me. – Jesus Christ, John 5:39.
When Jesus Christ made the statement above, the “scriptures” at the time consisted solely of the Old Testament. And it raises a question that is often asked in the church – where is Jesus Christ in The Old Testament? Was Jesus sitting in Heaven just observing the world during the time of the Old Testament or was He actively interacting with humanity and appearing all throughout the Scriptures? This article will show that Jesus Christ indeed appears throughout the Old Testament and that the concept of God existing in more than one person was well-understood in ancient Jewish culture. And the mysterious Angel of The Lord, featured in the Old Testament, is indeed the Savior, Jesus Christ.
The Testimony of Jesus Christ Himself
The Book of John provides the answer all on its own.
No man hath seen God at any time, the only begotten Son, which is in the bosom of the Father, he hath declared him. – John 1:18.
Not that any man hath seen the Father, save he which is of God, he hath seen the Father. – John 6:46.
These two verses alone provide compelling Biblical evidence that Jesus Christ physically appears in the Old Testament. In both verses above The Lord Jesus Christ quite clearly states that no man has ever seen God The Father except for Him. Thus it would automatically follow that any physical appearance by God in the Old Testament was not God the Father and thus was The Son, Jesus Himself.