1 Corinthians 9:7-9

7[Consider this:] Who at any time serves as a soldier at his own expense? Who plants a vineyard and does not eat its fruit? Or who tends a flock and does not use the milk of the flock?

8Do I say these things only from a man’s perspective? Does the Law not endorse the same principles?

9For it is written in the Law of Moses, “You shall not muzzle an ox while it is treading out the grain [to keep it from eating the grain].” Is it [only] for oxen that God cares?