Arthur Schopenhauer, The World as Will and Representation, tr. E. F. J. Payne, vol. II (Dover, 1966), p. 162. This is from Chapter XVII, "On Man's Need for Metaphysics" (emphases added and a paragraph break):
Temples and churches, pagodas and mosques, in all countries and ages, in their splendour and spaciousness, testify to man's need for metaphysics, a need strong and ineradicable, which follows close on the physical. The man of a satirical frame of mind could of course add that this need for metaphysics is a modest fellow content with meagre fare. Sometimes it lets itself be satisfied with clumsy fables and absurd fairy-tales. If only they are imprinted early enough, they are for man adequate explanations of his existence and supports for his morality.
Consider the Koran, for example; this wretched book was sufficient to start a world-religion, to satisfy the metaphysical need for countless millions for twelve hundred years, to become the basis of their morality and of a remarkable contempt for death, and also to inspire them to bloody wars and the most extensive conquests. In this book we find the saddest and poorest form of theism. Much may be lost in translation, but I have not been able to discover in it one single idea of value. Such things show that the capacity for metaphysics does not go hand in hand with the need for it . . . .