In Twilight of the Idols, he wrote, “When one gives up the Christian faith, one pulls the right to Christian morality out from under one’s feet. This morality is by no means self-evident. . . . By breaking one main concept out of [Christianity], the faith in God, one breaks the whole: nothing necessary remains in one’s hands.”
33. Friedrich Nietzsche, “Skirmishes of an Untimely Man,” chap. 8 of The Twilight of the Idols, in The Portable Nietzsche, ed. and trans, Walter Kaufmann (New York: Penguin, 1976), 515–16.