You're lucky your brain protected you from how garbage the movie was.
You...might have forgotten exactly what happened. Luke looked into Ben's mind, similar to reading Vader's feelings during their RotJ fight and sensing conflict in him, and what he saw in Ben was a terrible, growing darkness that posed a threat to everything he ever loved.
At no point did some outside voice in the Force tell him to do anything. It was his most basic instinct, that trickle of the dark side in him...the same trickle of darkness that made him lose his cool and violently attack Vader in RotJ. He ignited his saber in "the briefest moment of pure instinct" because his first impulse was to stop the threat...but he never ACTUALLY intended to kill him. He never made an attack.
If Ben hadn't woken up, Luke would have turned off his saber and left.
I don't think you have the faintest idea what you're talking about. Did you watch it once, misinterpret it horribly, and then play telephone with your own imagination until the scene warped into something it never was? I legitimately don't know how you could get the impression that a "magic god" told Luke he needed to kill Ben. That's not even close to true.
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I write Naruto Fanfiction. But I am definitely not a furry.