Christian theologians and philosophers spent over a thousand years trying to reconcile god being omniscient, omnipotent, and omnibenevolent, the existence of evil, our having free will, etc. They never could really do it, because it doesn't make sense (IMO). The tripple omni god thing really comes outta Greek philosophy and doesn't really fit in with what's in the bible at all.

I'm not a Christian, but really the only good answer is that it's a mystery. That sounds kinda like cope and I think it probably is just that for some. But I don't think it necessarily is, there is a deeper meaning to mystery as well.