Everything that is contrary to right reason is sin. Accordingly, therefore, the philosophers think fit to define the most generic passions thus: lust, as desire disobedient to reason; fear, as weakness disobedient to reason; pleasure, as an elation of the spirit disobedient to reason. If, then, disobedience in reference to reason is the generating cause of sin, how shall we escape the conclusion, that obedience to reason—the Word—which we call faith, will of necessity be the efficacious cause of duty? For virtue itself is a state of the soul rendered harmonious by reason in respect to the whole life. Nay, to crown all, philosophy itself is pronounced to be the cultivation of right reason; so that, necessarily, whatever is done through error of reason is transgression, and is rightly called, (ἁμάρτημα) sin. Since, then, the first man sinned and disobeyed God, it is said, “And man became like to the beasts:” being rightly regarded as irrational, he is likened to the beasts. Whence Wisdom says: “The horse for covering; the libidinous and the adulturer is become like to an irrational beast.” Wherefore also it is added: “He neighs, whoever may be sitting on him.” The man, it is meant, no longer speaks; for he who transgresses against reason is no longer rational, but an irrational animal, given up to lusts by which he is ridden (as a horse by his rider).