12:21 Paul’s fatherly ties with the Corinthian church are strong, and he knows that if he returns to find some of them (his “children,” v. 14) still unruly, it will be humiliating for him, just as parents are humiliated by the misbehavior of their children.

many of those who sinned earlier and have not repented. False apostles were not the only problem in Corinth. There were some people still engaging in sin, and Paul warns them.