1 Corinthians 9:17-19
New Century Version
17 If I preach because it is my own choice, I have a reward. But if I preach and it is not my choice to do so, I am only doing the duty that was given to me. 18 So what reward do I get? This is my reward: that when I tell the Good News I can offer it freely. I do not use my full rights in my work of preaching the Good News.
19 I am free and belong to no one. But I make myself a slave to all people to win as many as I can.Read full chapter