[jbeninger]

A character asks that question in Hyperion, by another sci-fi author (Dan Simmons).

The answer he arrived at was that God was not testing Abraham. He was allowing Abraham to test God. When God stayed his hand at the last moment, he knew that he'd met a god worth following.

(I'm not religious myself, but I did find this to be an interesting-enough interpretation to parrot it back to you on a web forum)

[Sharlin]

No, I was talking about Jesus (I believe the GP was as well).

The Jesus situation is an interesting inversion of the Abraham dilemma though. This time God is prepared to sacrifice his own son – but we sort of failed the test by design, executing the sacrifice as planned even though we could have just let Jesus live. Not sure what it says about us or God.