Is God the God of Abraham?
It seems impossible: How could “of Abraham” be a description of God if Abraham’s existence is contingent (as it certainly is)?
Should we then say that God is not essentially the God of Abraham but only voluntarily so? That solution doesn’t satisfy either: First, because it leaves us wondering who this not-God-of-Abraham God actually is ; second and more importantly, because it runs afoul of God’s own self-naming: “Yahweh the God of your fathers, the God of Abraham . . . this is My Name forever” (Exodus 3:15).
Some things that are true of God would not be true of God unless He created the world. He would not be Creator, the God of Exodus, or the God of resurrection unless He created Adam and Abraham, delivered Israel from Egypt, and raised Jesus from the dead.
The biblical data forces the conclusion that God is the God of Abraham, that His name incorporates a contingent creature. However we make sense of that, we need to make sense of it, rather than search for a back door that would enable us to escape the challenge.