There are several cases in Fahrenheit 451 where it is clear that Christianity, while evidently extremely rare, is still heard of. For instance, Faber notes that Jesus is still known, though in a much different form than before:
"It's as good as I remember. Lord, how they've changed it - in our 'parlours' these days. Christ is one of the 'family' now. I often wonder it God recognizes His own son the way we've dressed him up, or is it dressed him down? He's a regular peppermint stick now, all sugar-crystal and saccharine when he isn't making veiled references to certain commercial products that every worshipper absolutely needs."
At the same time, the Bible (a copy of which Montag saved from a house before it was burned) is evidently no longer read, and certainly not held in any high importance. This is highlighted when Mildred asks Montag, "Who's more important, me or that Bible?"
Is religion at all a factor in the society, and if so, has it played a role in keeping old literary fables and stories alive, if only in the oral tradition? Has Christianity - or other religions - been a source of conflict and rebellion against the overwhelmingly anti-literary world?