Paul advises us to cleanse ourselves for the apocalypse. He also urges us to make rooms in our hearts for him and his friends, and claims they haven't corrupted anyone. He says he's proud of the Corinthians for making Macedonia safe for him and Titus, who has told him how much they miss him. He says he doesn't regret sending his last letter, even though it made them sad for awhile, but it did make them repent, and hopefully stop banging their stepmothers, so he's happy he sent it.
Apparently holy sorrow leads us to heaven, but worldly sorrow leads us to hell. But now the Corinthians are back on the right track. He closes by reassuring them that Titus loves them in his heart and that he himself is confident in them.
Paul will now give us a list of all the good things the churches have done in Macedonia. The congregation is poor in monetary terms, but spiritually generous. They gave a big donation to the poor Christians in Jerusalem. They can expect a future begging visit from Titus. Paul isn't commanding them, just setting them up for a friendly competition with other churches to see who can raise the most cash, just like Jesus. He says the Corinthians have a good shot, since they won last year, but reminds them not to give more than they can afford. He assures them that later on, when they need money, the Jerusalem crowd will pay it forward. Unless the world ends, of course.
Paul promises to send someone along with Titus for extra exhorting, but supposedly because the church wants to be completely transparent in its cash dealings, the first and last time one of them made that claim.