Thus Spake Zarathustra: A Book for All and None. Friedrich Wilhelm Nietzsche

lest it become the road to hell—to filth and lust of soul.

      Do I speak of filthy things? That is not the worst thing for me to do.

      Not when the truth is filthy, but when it is shallow, doth the discerning one go unwillingly into its waters.

      Verily, there are chaste ones from their very nature; they are gentler of heart, and laugh better and oftener than you.

      They laugh also at chastity, and ask: “What is chastity?

      Is chastity not folly? But the folly came unto us, and not we unto it.

      We offered that guest harbour and heart: now it dwelleth with us—let it stay as long as it will!”—

      Thus spake Zarathustra.