Why must God rest?

I clocked in 4 hours of church this Easter weekend and one of the readings that came up was from Genesis, which got me thinking. God is generally accepted as an all-powerful-omnipotent-being... so why did he need to rest on Sunday? Now we must assume this is symbolic, after all there wasn't a calender at the begining of time, much less one like today's. I would go further to say that most of the Bible is symbolic, meaning not literal, especially the Old Testament.

Adam and Eve then, literal or sympolic? If symbolic then all those "theories" of evolution could be true. I am more of a science-minded guy, so I know that the evidence of evolution makes it more then just a theory. And if Adam and Eve was just a moralty story, that means original sin is most likely not the case. That means there is a major crack in most Christian religions.

I'm not trying to disprove Christianity. I, for one, believe most of the new testament to be literal, which is not easy to do considering the miracles preformed thoughout go against science as well. It is just easier for me to accept the version of God portrayed here, then the God of the old testament that often went against his own commandments.