1 Corinthians 9:12, 14, 18, 23

If others be partakers of this power over you, are not we rather? Nevertheless we have not used this power; but suffer all things, lest we should hinder the gospel of Christ.

Even so hath the Lord ordained that they which preach the gospel should live of the gospel.

What is my reward then? Verily that, when I preach the gospel, I may make the gospel of Christ without charge, that I abuse not my power in the gospel.

And this I do for the gospel's sake, that I might be partaker thereof with you.