Read 2 Corinthians 2:1-4
Paul’s phrase “another painful visit” indicates that he had already made one difficult trip to Corinth since founding the church. Paul had gone there to deal with those in the church who had been attacking and undermining his authority as an apostle of Jesus Christ, thus confusing other believers.
Paul’s last letter, referred to here, was not the book of 1 Corinthians, but a letter written between 1 and 2 Corinthians, just after his unplanned, painful visit. Paul refers to this letter again in chapter 7.
Paul did not enjoy reprimanding his friends and fellow believers, but he cared enough about the Corinthians to confront them with their wrongdoing. Proverbs 27:6 says, “Wounds from a friend are better than many kisses from an enemy.” Sometimes our friends make choices that we know are wrong. If we ignore their behavior and let them continue in it, we won’t be showing love to them. We show love by honestly sharing our concerns in order to help these friends be their very best for God. When we don’t make any move to help, we show that we are more concerned about being well liked than about what will happen to them.