7:5 For indeed, when we came to Macedonia, our bodies had no rest, but we were troubled on every side. Outside were conflicts, inside were fears. 6 Nevertheless God, who comforts the downcast, comforted us by the coming of Titus, 7 and not only by his coming, but also by the consolation with which he was comforted in you, when he told us of your earnest desire, your mourning, your zeal for me, so that I rejoiced even more.
8 For even if I made you sorry with my letter, I do not regret it; though I did regret it. For I perceive that the same epistle made you sorry, though only for a while. 9 Now I rejoice, not that you were made sorry, but that your sorrow led to repentance. For you were made sorry in a godly manner, that you might suffer loss from us in nothing. 10 For godly sorrow produces repentance leading to salvation, not to be regretted; but the sorrow of the world produces death. 11 For observe this very thing, that you sorrowed in a godly manner: What diligence it produced in you, what clearing of yourselves, what indignation, what fear, what vehement desire, what zeal, what vindication! In all things you proved yourselves to be clear in this matter. 12 Therefore, although I wrote to you, I did not do it for the sake of him who had done the wrong, nor for the sake of him who suffered wrong, but that our care for you in the sight of God might appear to you.
It's difficult to know for certain but it seems Paul is referring to the letter he wrote them which we know as 1 Corinthians. The reason why it's difficult to know for sure is because he alludes in both letters we have to other letters which we don't have. However since the lessons to be learned remain the same either way, it doesn't really matter. If it was 1 Corinthians he is referring to we know the situation. He wrote chastising them because a man in the church was openly sleeping with his father's wife (we presume not his mother but can't be sure). Paul was upset not just because of the situation but the fact the church was letting it slide as if nothing was wrong.
I want you to notice Paul's admission about the whole thing. He found out what was happening, was likely tortured trying to figure out how to respond. He decides to write the letter. Apparently it was not well received at first and for a time Paul was sorry he had sent it. In time though the church came to grips with their role and responsibilities in the matter and dealt with it. Now Paul is remembering all that to them in this letter and telling them how he went through the roller coaster of emotions but ultimately is thankful he did what he did because it had the desired result and more importantly it was the right thing to do. As Jesus said "Those I love I rebuke and correct."
Paul has a reason for reminiscing. He knows this letter may upset them as well. None of likes being corrected. We get defensive, pride is awakened, and we get offended. You can just imagine the reaction. "First you get mad at us because a guy is doing something wrong and we didn't do anything about it. Now you're mad because a guy did something wrong, we did correct it and now you think we're not being nice enough to him. First it was 'Have nothing to do with that guy' and now it's 'Comfort the poor bad guy so he doesn't feel so bad about what he did'.
Easy for pride to mess with our thinking isn't it? Now you can see why Paul spends more time telling them how much he loves them and desires their good. He does not want to leave any room for distorted thinking and a negative, destructive reaction. He loves them and his counsel is only for their good. He reminds them how much he has suffered along with his companions to bring them the gospel in the first place and how much he has suffered within himself trying to keep them connected with Jesus and free from the land mines of the enemy.
Love suffers long and is kind and we can certainly see that as Paul continues to shepherd Corinth long after his departure. As a pastor I too struggle to know when to speak and when to remain silent, when to risk offending in order to correct and when to give people space and time to figure things out on their own. I'm glad to know Paul had those struggles too. I'm glad to know he did things he regretted only to learn in time it was the right thing to do.
Loving others is hard. It requires wisdom, courage, tact, compassion, and a host of other qualities I lack. I'm thankful Jesus never stops being my Shepherd even when He tells me things I don't want to hear.