Deuteronomy 18:3-5

3This is the priests’ share from the people who offer a sacrifice, whether it is an ox, a sheep, or a goat; the priests are to be given the shoulder, jaws, and stomach.

4You are to give him the firstfruits of your grain, new wine, and fresh oil, and the first sheared wool of your flock.

5For the Lord your God has chosen him and his sons from all your tribes to stand and minister in his name from now on.