John Calvin Commentary 2 Corinthians 12:19

"Ye think all this time that we are excusing ourselves unto you. In the sight of God speak we in Christ. But all things, beloved, [are] for your edifying." — 2 Corinthians 12:19 (ASV)

Do you again think. Since those who are conscious of some wrongdoing are sometimes more anxious than others to clear themselves, it is probable that this, too, was turned into a ground for slander—that Paul had in the previous letter devoted himself to a defense of his ministry. Furthermore, it is a fault in the servants of Christ to be too concerned about their own reputation.

Therefore, with the aim of repelling those slanders, he declares in the first place that he speaks in the presence of God, whom evil consciences always dread. In the second place, he maintains that he has not so much regard for himself, as for them. He was prepared to go through good report and bad report, (2 Corinthians 6:8), indeed, even to be reduced to nothing; but it was advantageous for the Corinthians that he should retain the reputation he deserved, so that his ministry might not be brought into contempt.