1 Corinthians 9:16-19

Telling the Good News does not give me any reason for bragging. Telling the Good News is my duty—something I must do. And how terrible it will be for me if I do not tell the Good News. 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. 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. I am free and belong to no one. But I make myself a slave to all people to win as many as I can.