Seems to me that the cold facts of the story available to the writer, are that Abraham and Isaac went up the mountain and came back down.
There is no good reason outside the story why we ought to believe that God communicated anything to Abraham in a manner different to how any religious person may feel that he is being communicated with by God.
Seems to me that the story is a bit circular, in that it is proposed that Abraham is hearing God's WILL more clearly because he has such faith, yet the story concerns God testing Abraham's faith.
Matt's idea that God can will the resurrection of anyone he chooses seems to make a mockery of the whole idea of Jesus death.
Are the Gospels telling the story to believers who understand God's plan through the exact same story?
Point is that minimizing the killing part, the death part of the Abraham story seems to be special pleading for the Abraham story and ONLY the Abraham story if your not willing to minimize the killing of Jesus in THAT story.
All I'm trying to say here is that shifting emphasis using rhetoric 'a la' Matt here, can have untended consequences for other stories.
If we're going to make a parallel between Isaac and Jesus, we could easily make an unflattering parallel between God hardening the Pharoah's heart and God presumably ignoring the faithful prayers of the Sanhedrin requesting their God's Will??
Can we assume that the Sanhedrin believed in God?Can we assume that the Sanhedrin believed that they were faithful to God and were exacting God's Will?
Then there must be different kinds of faith then?
Or I'm missing something extremely subtle.