In 1 Corinthians 5:1–13 Paul discusses the first area where repentance is needed. Among the Corinthian believers there is a brother who is living in gross sexual immorality (in Greek, porneia). The church is guilty of tolerating this brother and his sin.

This man is in a sexual relationship with his father’s wife, that is, with his stepmother (see further Leviticus 18:8; Leviticus 20:11; Deuteronomy 27:20). It is not said whether his father had died or whether this is a case of an extramarital affair. In either case, the verb has (echein) indicates that the sinful relationship is of an ongoing nature.

To say that this form of immorality is not tolerated even among pagans is not to say that it never occurs in the pagan world. Paul’s point is that even among the pagans, this kind of relationship is viewed as shameful and scandalous. Even in the ancient laws of pagan societies, such relationships were prohibited.