What Is The True Purpose Of Religion?

[Angrboda]

I'm kind of jumping in the middle here, so if what I say has been said -- sue me.

Somewhat akin to Minimalist's quote of Aristotle, religion and revealed truths are a useful tool for legitimizing authority, from the Delphic Oracles to the Pharoahs of Egypt, to the justification of Jewish kings to the Roman Caesar, and on into the first few millennia in the form of divine right of kings -- China took a similar route in justifying rulers with reference to a mandate of heaven, which, much like Jewish kingship, was summarily withdrawn from disliked rulers. Putting the blessing of god or gods upon the authority of your rulers saves a lot of messy recourse to appealing to the populace's self-interest.

I'm sure there are other generic pragmatics of religion quite apart from simply shaping the behavior of the believers, but divine right is the one that pops to mind most readily.

Oh, ETA: Probably the most universal use of religion, explaining phenomena which aren't understood, and giving people the illusion of control and order (and meaning) where frequently there is none to be had.