Hermann Ebbinghaus,
Psychology: an elementary text-book
“ But religion is, naturally and unfortunately, a mighty weapon in the hands of the masters defending their positions against the slaves. Religion gives peace, quiescence, to the human heart. Religion perhaps teaches that the splendor of wealth is insignificant, worthless; that the poor are better off in the future, eternal life, than those who are now rich. Religion perhaps even teaches that those who do not believe this will be severely punished in the next life. This is not the original meaning of the doctrine—that the wretched should remain wretched ”
