As long as a population can be induced to believe in a...

As long as a population can be induced to believe in a supernatural hereafter, it can be oppressed and controlled. People will put up with all sorts of tyranny, poverty, and painful treatment if they're convinced that they'll eventually escape to some resort in the sky where lifeguards are superfluous and the pool never closes. Moreover, the faithful are usually willing to risk their skins in whatever military adventure their government may currently be promoting.