Paul announces his third visit and cites Deuteronomy 19:15, that every charge must be established by two or three witnesses. He warns that he will not spare those who continue in sin. The Corinthians demanded proof that Christ speaks through Paul. Paul answers with the pattern of the cross. Christ was crucified in weakness but lives by the power of God, and Paul shares both Christ's weakness and His resurrection power in dealing with them.
Paul reverses their demand for proof. They should examine and test themselves to see whether they are in the faith, recognizing that Jesus Christ is in them, unless they fail the test. Paul is confident they will see that he has not failed. His real prayer, however, is not for his own vindication but for their good. He wants them to do what is right even if he appears weak. He rejoices when he is weak and they are strong, and he prays for their restoration, or completeness.
Paul explains that he writes severely while absent so that he need not use severity in person, since the Lord's authority is for building up. His final words gather the themes of the letter into five commands: rejoice, aim for restoration, comfort one another, agree with one another, and live in peace. The promise follows that the God of love and peace will be with them. The letter ends with one of the clearest Trinitarian blessings in the New Testament: the grace of the Lord Jesus Christ, the love of God, and the fellowship of the Holy Spirit.