If i found out i was the "reincarnated spirit" of a jewish arab from two thousand years ago, whose mother claimed to be a virgin (because sexual relation outside marriage would be justification for stoning her to death), who had spent most of my "previous life" as one of thousands of preaching messiahs, only to find out what perverted, twisted form my already somewhat lunatic teachings had taken? Well, i think i would try to either stay out of the way as much as possible or try to undo the terrible things done in the name of the new form my original teachings had taken.
Oh, you just wanted to know what i would do with unlimited supernatural powers? Yeah, the entire universe is now my lab, and i will be conducting every conceivable experiment i can think of by creating and destroying worlds and observing the universe, while messing with it sometimes for more specific experiments (Adding volcanoes and throwing meteorites in heavily populated areas, SimCity style).
(I really need to work on those run-on sentences)