Once St. Louis, king of France asked a friend: “Would you rather have leprosy or commit a mortal sin?” His friend, without any hesitation, answered: “Your Majesty, I would rather commit 30 mortal sins than become a leper.” The king replied: “I am very sorry for you, for you do not really understand what is a mortal sin.”
Saint Louis was right: having a body afflicted with an incurable disease, such as leprosy was in his time, is far better than having a soul deadened by sin. Many reasons can be given to justify this statement, but I wish to simply focus on one—the harm that sin inflicts on the one who commits it, as sin carries within itself its own punishment.
The sinner is wretched not only because God may punish him by humiliating him with sins that make him understand his nothingness and misery; he is wretched not only because he will face the painful consequences of his wickedness in the next life; but he is wretched also because his very sin is both guilt and punishment.
Sin is a moral punishment and, if we may say so, an ontological one. Hence, Saint Thomas Aquinas affirmed in his commentary on Boethius’s De Trinitate that “it is inherent in the creature that its separation from God entails a decline from what he is.” And elsewhere, speaking of how sin harms the person, he says: “sin wounds the person who commits it” (Summa Theologica, III, 19, 4 ad 1).
Clearly, this decline from what one is, this harm or diminishment, that occurs in a spiritual order, is imperceptible to human—or rather, worldly—eyes. To explain more precisely, sin entails a deterioration in the rational order of man and this impairment in the rational order simultaneously brings about a loss of human dignity: “By sinning man departs from the order of reason, and consequently falls away from the dignity of his manhood, in so far as he is naturally free, and exists for himself, and he falls into the slavish state of the beasts…” (Summa Theologica, II-II, 64, 2 ad 3).
