My take on the Abraham story isn't so much a divine punk'd or practical joke but as something like the whole terrifying prison subplot of V for Vendetta -- God knew no more human sacrifices were needed, ever, and knew the depths of Abraham's faith that all would be well and all would be well and all manner of things would be well no matter how shitty and awful and impossible it seemed, but Abraham didn't, not until he got pushed to it. And when he got pushed, and knew straight to his bones that truth about himself, he was able to walk away free and clear and with his beloved sacrifice his to keep, forever, and the promise of no such beloved sacrifices, ever again.
Not that the prison subplot in V For Vendetta isn't itself totally fucked-up and harrowing and sick and wrong, but it's also messy and heartbreaking and V's motives run much deeper and more resonant than "Punk'd ya, Evey!" And alongside her utter rage and fury at the whole fucked-up mess, Evey feels a sort of dark and profound amazement at what she now knows about herself, knows in a way she never could have if she hadn't been made to believe the stakes were just that high.
Of course, I post all this in the full knowledge that probably everyone on earth, with the possible exceptions of Alan Moore and maybe victor, will think I'm on the crackiest crack that ever was cracked.