God rewards the faithful, either in this life or the next. The faithful do not know when these rewards will come, but they can be confident that they will come—eventually. Moreover, God does not ask for much in exchange. God requires only that the faithful be faithful, that is, that they trust in him and manifest their trust by praying, joining in worship services, supporting their church (or mosque, temple, whatever), and following his commands—as interpreted by self-appointed spokespersons, naturally. Distilled to its essential core, this is and has been the message of most religions from ancient times to the present. Sure, there are variations. Typically each religion now has a deity instead of deities, and today’s deity seems more concerned about what we characterize as moral rules than some past deities whose concerns focused more on ritual observance. But these differences are nuances in the core message.
And it’s a powerful message. Its power is exhibited by the fact that it remains attractive to most inhabitants of this planet, even when belief in supernatural agents has lost all intellectual respectability. In the infancy of humanity, belief in supernatural agents had some empirical justification. The existence of the gods seemed to explain things that otherwise escaped our understanding. If our ancestors did not understand the natural causes of wind, rain, drought, flooding, fertility, disease, and so forth, it’s not surprising that they attributed such phenomena to an agent or agents, and obviously such agents had to possess powers far exceeding our own. But for modern humans—except for those who are ignorant, willfully or otherwise—the gods explain nothing.