Why did Paul write a severe letter to the Corinthians?
Paul wrote the severe letter to address problems in the Corinthian congregation and to correct their opposition and condemnation of him. He explained that although it made them sorry, he did not regret it because it had to be done.
Les explains that Paul was at Ephesus while Titus was at Corinth. Paul had written a letter to the Corinthians in which he had to dress them down severely, because he had heard things from the Corinthian congregation that were against him and condemning him. Titus later brought back good news that the Corinthians still loved Paul and held him in high esteem, which thrilled Paul. In verse 8, Paul says that though he made them sorry with a letter—the first Corinthian letter, where he addressed their problems—he did not repent or regret it, because it had to be done.