But God, who comforts the downcast, comforted us by the coming of Titus, and not only by his coming but also by the comfort you had given him. He told us about your longing for me, your deep sorrow, your ardent concern for me, so that my joy was greater than ever.2 Corinthians 7:6-7
Reading through second Corinthians, you'll see that Titus gets mentioned quite a bit. Paul's refreshed by his very presence, and his news too; Titus had been comforted in Corinth and he passes that on to Paul. It's a big deal for Paul because he hasn't been having a very pleasant time, thus the self-referencing with the word "downcast" in verse six.
What I want to point out to you with this passage and the reference to Titus in second Corinthians in general is that we have such power to refresh our brothers and sisters in the Spirit. Serving them to help them out or even just contacting them to see how they're doing (which we have a multitude of ways to do) can be a very encouraging thing to a downcast Christian, even if they're just carrying their usual burdens.
Always be looking for opportunities to serve!