Deuteronomy 18:3-5

New Revised Standard Version, Anglicised

³ This shall be the priests’ due from the people, from those offering a sacrifice, whether an ox or a sheep: they shall give to the priest the shoulder, the two jowls, and the stomach. ⁴ The first fruits of your grain, your wine, and your oil, as well as the first of the fleece of your sheep, you shall give him. ⁵ For the Lord your God has chosen Levi^[a] out of all your tribes, to stand and minister in the name of the Lord, him and his sons for all time.