What does 2 Corinthians 7:7 mean?
Paul and his companions were "downcast." Verse 6 used a Greek term referring to humility, lowliness, and being "low". They were suffering affliction from several sources. One of those was that they did not know where Titus was. Traveling in the ancient world could be dangerous, and they were concerned for his safety. In addition, Paul did not know how the Corinthians had responded to a severe and corrective letter he had written to them after his previous painful visit with them. While we do not have the text of that letter, we learn about it in 2 Corinthians.God comforts the downcast, however, and Paul reported that God provided comfort through Titus' arrival. Now he clarifies. They were comforted to find that Titus was safe, but they were also comforted by hearing Titus' report about how the Corinthians had comforted him, especially in their response to Paul's letter.
How had the Corinthians responded? They had spoken of their longing for Paul. They had described their mourning or grief about their sinfulness and their enthusiastic support of Paul. In short, they had repented of their sin and expressed their affection for Paul. This was all he could have hoped for. Paul experienced not just comfort in hearing this, but he also experienced great joy.