Why is there evil in the world, if God is all-powerful and good?

[Esiar]

Well, questioning whether or not God is all-powerful (if he exists) isn't really the question here, it's whether or not he'd be good by allowing evil to happen. The only explanation that I can think of is that God would give people free will. You can see at least from the Bible, that he made all things good (Even Lucifer/Satan).

I guess you could say that he is a good and all-powerful God, who made a good creation, that had the ability to corrupt itself. But if you go deeper than that, you would have to ask if letting people do that is moral, which I don't know if that would be.