Nicene and Post-Nicene Fathers: Series I/Volume I/Confessions/Book VII/Chapter 16

Chapter XVI.—Evil Arises Not from a Substance, But from the Perversion of the Will.

22. And I discerned and found it no marvel, that bread which is distasteful to an unhealthy palate is pleasant to a healthy one; and that the light, which is painful to sore eyes, is delightful to sound ones. And Thy righteousness displeaseth the wicked; much more the viper and little worm, which Thou hast created good, fitting in with inferior parts of Thy creation; with which the wicked themselves also fit in, the more in proportion as they are unlike Thee, but with the superior creatures, in proportion as they become like to Thee. And I inquired what iniquity was, and ascertained it not to be a substance, but a perversion of the will, bent aside from Thee, O God, the Supreme Substance, towards these lower things, and casting out its bowels, and swelling outwardly.