Adam Clarke on Philippians 1:5

For your fellowship in the Gospel - if we consider κοινωνια as implying spiritual fellowship or communion, then it signifies, not only their attention to the Gospel, their readiness to continue it, and perseverance in it, but also their unity and affection among themselves. Some understand the word as expressing their liberality to the apostle, and to the Gospel in general; for the term may not only be applied to communion among themselves, but to communications to others. This sense, though followed by Chrysostom and Theophylact, does not appear to be the best; though we know it to be a fact that they were liberal in supplying the apostle's necessities, and, no doubt, in ministering to the support of others.