What does 2 Corinthians 12:20 mean?

Paul asked in the previous verse if the Corinthians thought he had been writing to defend himself to them. He has certainly made a defense, and countered false charges. And yet, Paul clarified, he is not defending himself to them because they determine his worth. They are not his judge and jury. He has been attempting to convince them that he is a true apostle for their sake, so that they will return to the path of pure devotion to the true Christ he represents (2 Corinthians 12:19).

Now he turns the tables. They, the believers in Corinth, are the ones who should be concerned about charges from Paul. Unlike them, Paul truly represents Christ and will come to them with the full authority of an apostle. He is concerned what sins he might find being actively practiced among them. He is also worried about what response may be necessary from them on behalf of Christ.

Paul makes a list of sins and attitudes. Perhaps he has received reports that the Corinthians were practicing these things. Perhaps the false apostles had led them into these. The list includes quarreling, jealousy, anger, hostility, slander, gossip, conceit, and disorder. Several of these have to do with division in the church, a problem Paul calls out often in Corinth (1 Corinthians 1:10–11). He doesn't want to find these things when he arrives to visit them next.