Paul's comfort because they had accepted his rebuke:
Related Commentaries of 2 Corinthians 7:5
2 Corinthians 7:5-8
5 For, when we were come into Macedonia, our flesh had no rest, but we were troubled on every side; without were fightings, within were fears.
6 Nevertheless God, that comforteth those that are cast down, comforted us by the coming of Titus;
7 And not by his coming only, but by the consolation wherewith he was comforted in you, when he told us your earnest desire, your mourning, your fervent mind toward me; so that I rejoiced the more.
8 For though I made you sorry with a letter, I do not repent, though I did repent: for I perceive that the same epistle hath made you sorry, though it were but for a season.