For if I make you sorry, who is he then that maketh me glad, but the same which is made sorry by me?

People's New Testament

2:2 For if I make you sorry, etc. The thought is, your sorrow, because rebuked, gladdens me on account of your repentance.

Wesley's Notes

2:2 For if I grieve you, who is he that cheereth me, but he that is grieved by me - That is, I cannot be comforted myself till his grief is removed.

Jamieson-Fausset-Brown Bible Commentary

2. For-proof that he shrinks from causing them sorrow ("heaviness").

if I-The "I" is emphatic. Some detractor may say that this (2Co 2:1) is not my reason for not coming as I proposed; since I showed no scruple in causing "heaviness," or sorrow, in my Epistle (the first Epistle to the Corinthians). But I answer, If I be the one to cause you sorrow, it is not that I have any pleasure in doing so. Nay, my object was that he "who was made sorry by me" (namely, the Corinthians in general, 2Co 2:3; but with tacit reference to the incestuous person in particular) should repent, and so "make me glad," as has actually taken place; "for . who is he then that?" &c.

Matthew Henry's Concise Commentary

2:1-4 The apostle desired to have a cheerful meeting with them; and he had written in confidence of their doing what was to their benefit and his comfort; and that therefore they would be glad to remove every cause of disquiet from him. We should always give pain unwillingly, even when duty requires that it must be given.