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.
With a letter - Greek, 'in the letter'; namely, the first letter.
I do not repent, though I did repent. Translate, 'I do not regret it, though I did regret it.' The Greek regret х metamelomai (G3338)] and repent х metanoeo (G3340)] are distinct. Paul was almost regretting, through parental tenderness and doubt of the result, his having by rebukes grieved the Corinthians; but now that he has learned from Titus the salutary effect produced on them, he no longer regrets it.
For I perceive ... - explanatory of 'I did regret it,' and parenthetical ('for I perceive that that letter did make you sorry, though But for a season') (2 Corinthians 2:2).