John Calvin Commentary 2 Corinthians 7:13

"Therefore we have been comforted: And in our comfort we joyed the more exceedingly for the joy of Titus, because his spirit hath been refreshed by you all." — 2 Corinthians 7:13 (ASV)

We received consolation. Paul was wholly intent on persuading the Corinthians that nothing was more eagerly desired by him than their advantage. Hence he says that he had shared in their consolation. Now their consolation had been this — that, acknowledging their fault, they did not merely take the reproof in good part but had received it joyfully. For the bitterness of a reproof is easily sweetened as soon as we begin to taste its profitableness to us.

What he adds — that he rejoiced more abundantly on account of the consolation of Titus, is by way of congratulation. Titus had been overjoyed to find them more obedient and compliant than could have been expected — even more, at finding a sudden change for the better. Hence we may infer that Paul’s gentleness was anything but flattery, since he rejoiced in their joy, so as to be, at the same time, mainly focused on their repentance.