Albert Barnes Commentary 2 Corinthians 7:12

"So although I wrote unto you, I [wrote] not for his cause that did the wrong, nor for his cause that suffered the wrong, but that your earnest care for us might be made manifest unto you in the sight of God." — 2 Corinthians 7:12 (ASV)

Wherefore, though I wrote unto you, etc. In this verse Paul states the main reason why he had written to them on the subject. It was not principally on account of the man who had done the wrong, or of him who had been injured; but it was from tender anxiety for the whole church, and in order to show the deep interest which he had in their welfare.

Not for his cause that had done the wrong. Not mainly or principally on account of the incestuous person (1 Corinthians 5:1). It was not primarily with reference to him as an individual that I wrote, but from a regard for the whole church.

Nor for his cause that suffered wrong. Not merely that the wrong which he had suffered might be rectified, and that his rights might be restored, valuable and desirable as that object was. The offence was that a man had taken his father's wife as his own (1 Corinthians 5:1), and the person injured, therefore, was his father. It is evident from this passage, I think, that the father was living at the time when Paul wrote this epistle.

But that our care, etc. I wrote mainly that I might show the deep interest which I had in the church at large, and my anxiety that it might not suffer from the misconduct of any of its members. It is from a regard for the welfare of the whole church that discipline should be administered, and not simply with reference to an individual who has done wrong, or an individual who is injured. In church discipline, such private interests are absorbed in the general interest of the church at large.