Deuteronomy 18:3-5

Revised Standard Version

³ And this shall be the priests’ due from the people, from those offering a sacrifice, whether it be ox or sheep: they shall give to the priest the shoulder and the two cheeks and the stomach. ⁴ The first fruits of your grain, of your wine and of your oil, and the first of the fleece of your sheep, you shall give him. ⁵ For the Lord your God has chosen him out of all your tribes, to stand and minister in the name of the Lord, him and his sons for ever.