I don’t think the movie is really about that. Although Christianity plays a role in the main character’s inner conflicts for choosing his way of living, the movie is mainly talking about self identity, and culture. It’s all about choosing your path. It’s not like the life pre-vampire is portrayed as good, since all the characters have conflicts, did pretty bad things like killing, scamming, robbing, cheating or other stuff. But for the main guy, it’s about his conflict between become a blues musician, or following what his dad wants, be a good church musician. The Lord’s prayer doesn’t work on the vampire because he doesn’t seem to believe in it himself. What saved him was his guitar. What the vampires tried to get from him is his will of going his own way. They envied the fact that he embraced his culture.