Philippians 1:5, 12, 16, 27

for your fellowship in furtherance of the gospel from the first day until now

Now I would have you know, brethren, that the things which happened unto me have fallen out rather unto the progress of the gospel

the one do it of love, knowing that I am set for the defence of the gospel

Only let your manner of life be worthy of the gospel of Christ: that, whether I come and see you or be absent, I may hear of your state, that ye stand fast in one spirit, with one soul striving for the faith of the gospel