In Exodus 3:14, the pre-incarnate Jesus, who is God spoke to Moses. Moses asked, who shall I say sent me. God said, "Tell them I AM sent me to you." Prior to this, God said, "I am the God of Abraham, Isaac and Jacob" as well.
This was God's introduction, not very descriptive, but it was to be fulfilled by Jesus. The "I AM" is complete when we look at these verses:
"I am the Light of the World"
"I am the Good Shepherd"
"I am the way, the truth and the life ..."
"I am the resurrection and the life"
"I am the door"
"I am the Bread which came down from heaven"
"I am the vine, you are the branches"
"I am the Alpha and the Omega"
"I am He" who was throughout the Old Testament, the LORD, prophesied as the SAVIOR/MESSIAH. And so He interacted with humans all along.
He is the CREATOR who emptied himself into a human baby and became a man and dwelt among us. All things were made by Him, For Him and through Him all things consist (hold together).
Only God can take our sins away, it requires Omniscience, Omnipotence and Omnipresence.
If you want to know what God is like, look at Jesus.