What does Philippians 1:4 mean?

Paul extends the thanks he began in verse 3. Specifically, he thanks God constantly, in every prayer, for what the Philippian church has been able to do. His expression of thanksgiving is all–inclusive, using "always," "every," and "all." Again, prayer is key, mentioned twice in this verse. This thanks is not only based in the success of the gospel in Philippi, but also in the generosity shown by the church in their support of Paul (Philippians 1:5).

In addition, Paul prays "with joy." Paul's focus on joy in this letter is clearly seen. Philippians 1:25 notes, "I know that I will remain and continue with you all, for your progress and joy in the faith." He will again mention joy in Philippians 2:2, 29 and 4:1. Joy comes to Paul from the Philippians in this verse as well as in Philippians 2:2 and 4:1; his work gives them joy in the faith (Philippians 1:25) and they are to receive Epaphroditus with joy (2:29).