For bodily things are nearer to us, from these therefore he introduced instruction. But it is not so now. For we ought not to be confined to figures, and shadows, but to adhere to the truth, and to uphold it: sin is the unclean thing. From that let us flee, from that let us abstain. “If you come near it, it will bite you.” Nothing is more unclean than covetousness. Whence is this manifest? From the facts themselves. For what does it not defile? The hands, the soul, the very house where the ill-gotten treasure is laid up.
But the Jews consider this as nothing. And yet Moses carried off the bones of Joseph. Samson drank from the jawbone of an ass, and ate honey from the lion, and Elijah was nourished by ravens, and by a widow woman. And tell me, if we were to be precise about these things, what can be more unclean than our books, which are made of the skins of animals? The fornicator, then, is not the only one that is unclean, but others more than he, as the adulterer. But both the one and the other are unclean, not on account of the intercourse, (for according to that reasoning a man cohabiting with his own wife would be unclean,) but because of the wickedness of the act, and the injury done to his neighbor in his nearest interests.
Do you see that it is wickedness that is unclean? He who had two wives was not unclean, and David who had many wives was not unclean. But when he had one unlawfully, he became unclean. Why? Because he had injured and defrauded his neighbor. And the fornicator is not unclean on account of the intercourse, but on account of the manner of it, because it injures the woman, and they injure one another, making the woman common, and subverting the laws of nature. For she ought to be the wife of one man, since it is said, “Male and female created He them.” And, “they two shall be one flesh.”
Not “those many,” but “they two shall be one flesh.” Here then is injustice, and therefore the act is wicked. Again, when anger exceeds due measure, it makes a man unclean, not in itself, but because of its excess. Since it is not said, “He that is angry,” merely, but “angry without a cause.” Thus every way to desire overmuch is unclean, for it proceeds from a greedy and irrational disposition. Let us therefore be sober, I beseech you, let us be pure, in that which is real purity, that we may be thought worthy to see God, through Jesus Christ our Lord, with whom, etc.
Source: Homilies on Titus (New Advent)