If one part of the body suffers, then all the other parts suffer with it. Or if one part of our body is honored, then all the other parts share its honor too.
I wrote you a letter for this reason: so that when I came to you I would not be made sad by those people who should make me happy. I felt sure of all of you. I felt sure that all of you would share my joy.
I boasted to Titus about you. And you showed that I was right. Everything that we said to you was true. And you have proved that the things that we boasted about to Titus are true.