"...the God of Abraham, the God of Isaac, and the God of Jacob.... This is My name forever" (Exod. 3:15).
In Exodus 3 God gives His name. I wrote something about the "I AM" part of it. See Finishing the Sentence.
But let me share a thought about this part of it: "the God of Abraham, the God of Isaac, and the God of Jacob."
These words are given twice in Exodus 3 and are quoted by Jesus in Luke 20. And the thought is this: Could this be an Old Testament way of saying "God the Father, God the Son, and God the Holy Spirit"? Think about it.
This name of God uses three persons and puts God with each one of them. Moreover, Abraham is nothing if not a father. Isaac is his son, his only son whom he loves - but is willing to sacrifice.
And what about Jacob? He's a distinct third person, so to speak, but much-related to the other two. You could even say that he proceeds from Abraham (the father) and Isaac (the son), the way we talk about the Holy Spirit in the Nicene Creed.
I'm convinced that God is revealing Himself as Trinity in Exodus 3. And He adds, "This is My name forever." Here in Exodus it has an Old Testament veil over it. When, in the New Testament, the veil is removed, it sounds like this: "In the name of the Father and of the Son and of the Holy Spirit."
Glory be to the Father and to the Son and to the Holy Spirit; as it was in the beginning, is now, and will be forever. Amen.