Whether it happened or not was never the focus except for
   critics. What was always important was that it was used as an
   extreme example of obedience - an unthinkable scenario. It's
   even more vivid in the case of Job. If you go through the
   teaching and theological texts through the history of the
   religions, this story was always used as an example with which
   to debate and discuss and compare to one's own life. Could you
   do it? Would you do it? Whether it happened or not wasn't
   questioned because it didn't matter. What mattered was the
   lesson it gives. A thought experiment. Then again, I find nearly
   all thought experiments ridiculous beyond a certain point: How
   many people use examples from movies (like the Matrix) to base
   their real lives on? But that's my bias.