1 Corinthians 9:13-18

Do you not know that those who are employed in the temple service get their food from the temple, and those who serve at the altar share in the sacrificial offerings? In the same way, the Lord commanded that those who proclaim the gospel should get their living by the gospel. But I have made no use of any of these rights, nor am I writing these things to secure any such provision. For I would rather die than have anyone deprive me of my ground for boasting. For if I preach the gospel, that gives me no ground for boasting. For necessity is laid upon me. Woe to me if I do not preach the gospel! For if I do this of my own will, I have a reward, but if not of my own will, I am still entrusted with a stewardship. What then is my reward? That in my preaching I may present the gospel free of charge, so as not to make full use of my right in the gospel.