John Calvin Commentary 2 Corinthians 12:11

"I am become foolish: ye compelled me; for I ought to have been commended of you: for in nothing was I behind the very chiefest apostles, though I am nothing." — 2 Corinthians 12:11 (ASV)

I have become a fool. Until now, he had, by various apologies, sought their forgiveness for what was contrary to his own custom and way of acting, and contrary, also, to propriety and what was due to his office as an Apostle — the publishing of his own praises. Now, instead of seeking forgiveness, he upbraids them, throwing the blame upon the Corinthians, who should have taken the initiative in this.

For when the false apostles slandered Paul, they should have vigorously opposed them and faithfully borne the testimony due to his merits. He chides them, however, at this point, lest those who were unfavorably disposed towards the Corinthians should misinterpret the defense he brought forward — a defense he was compelled to make by their ingratitude — or persist in slandering him.

For in nothing. We are ungrateful to God if we allow His gifts, of which we are witnesses, to be disparaged or despised. He charges the Corinthians with this fault, for they knew him to be equal to the chiefest Apostles, and yet they listened to slanderers when they slandered him.

By the chiefest Apostles, some understand his rivals, who presumptuously claimed precedence. I understand it, however, as meaning — those who were chief among the twelve. “Let me be compared with any one of the Apostles; I have no fear that I shall be found inferior.”

For although Paul was on the best of terms with all the Apostles, so that he was prepared to extol them above himself, he nevertheless contended against their names when falsely assumed. The false apostles abused this pretext: that they had been in the company of the twelve, that they knew all their views, that they were fully acquainted with all their practices, and similar claims. Hence Paul, perceiving that they falsely gloried in these masks and counterfeit titles and were successful to some extent among less knowledgeable people, judged it necessary to enter upon such a comparison.

The correction that he adds — though I am nothing, — means that Paul was not inclined to claim anything as his own, but simply gloried in the Lord, (2 Corinthians 10:17), unless, perhaps, you prefer to consider this a concession, in which he mentions what is alleged against him by adversaries and slanderers.