1 Corinthians 5:1

It is actually reported that there is fornication among you, and such fornication as is not even among the Gentiles, that one of you hath his father's wife. [i. e., his step-mother. She was probably a pagan, and hence is not rebuked. The offense of the Corinthians had been magnified in that they had let Paul find out their sin by public gossip. Though they had written to him seeking light on other matters (1 Corinthians 7:1), they had not even mentioned this deplorable wickedness. Such incest was of course condemned by the Jewish law (Leviticus 18:8; Deuteronomy 27:20). But even Corinth, moral cesspool that it was, would be scandalized by such a crime, for it was condemned alike by Greeks and Romans. See the Oedipus of Sophocles, the Hippolytus of Euripides, and Cicero's Pro Cluentio, 5. As to such a case Cicero uses these words: "Oh, incredible wickedness, and--except in this woman's case--unheard in all experience!"]