Well the idea behind it is that nothing, not even god (if there is a god which I think there is) is all-powerful. There are some things that just are, and could not be any other way. Like the sin and morality thing--even if there was no god, certain things would still be right and other things would be wrong. Therefore, once you add a god into the picture, he/she doesn't have the ability to change that. But, right vs. wrong depends a lot on perception--for example when Hitler came into power, he taught the Germans that the Jews were evil, and they believed him. Most people now, however, don't think Jews are evil. Still though I think right and wrong still exist, just not totally in black and white.