2 Corinthians 12:21 And lest, when I come again, my God will humble me among you, and that I shall bewail many which have sinned already, and have not repented of the uncleanness and fornication and lasciviousness which they have committed.

The Apostle Paul sought to visit the church of Corinth again. After all, these Corinthians were Paul’s joy and crown of rejoicing. They were his glorying. He certainly did not want to come to them and have to be ashamed of them. Neither did he want to have to mourn over many who had sinned and had not repented of their uncleanness, fornication, and lewdness. [MacDonald]

He was sad to know that there are these prevailing sins in the church. There was no one mentioned but it is implicit that these ones were in the church. MacDonald observed well, “But it cannot be assumed that they were true believers. It specifically says they practiced these sins, and Paul elsewhere makes it clear that anyone whose life is characterized by such behaviour cannot inherit the kingdom of God (1 Cor. 6:9, 10). The apostle would mourn over them because they had not repented and would therefore have to be excommunicated.”