A.T. Robertson Commentary Philippians 1:5

"for your fellowship in furtherance of the gospel from the first day until now;" — Philippians 1:5 (ASV)

For your fellowship (επ τη κοινωνια υμων). "On the basis of your contribution" as in 2 Corinthians 8:4; 9:13; Acts 2:42. The particular kind of "partnership" or "fellowship" involved is the contribution made by the Philippians for the spread of the gospel (1:7 συγκοινωνους and 4:14 where συγκοινωνησαντες occurs).

In furtherance of the gospel (εις το ευαγγελιον). "For the gospel."

From the first day until now (απο της πρωτης ημερας αχρ του νυν). As when in Thessalonica (Php 4:15f.), in Corinth (Acts 18:5; 2 Corinthians 11:7–10), and now in Rome.