Deuteronomy 18:1-5

The Levitical priests—indeed, the whole tribe of Levi—are to have no allotment or inheritance with Israel. They shall live on the food offerings presented to the LORD, for that is their inheritance. They shall have no inheritance among their fellow Israelites; the LORD is their inheritance, as he promised them. This is the share due the priests from the people who sacrifice a bull or a sheep: the shoulder, the internal organs and the meat from the head. You are to give them the firstfruits of your grain, new wine and olive oil, and the first wool from the shearing of your sheep, for the LORD your God has chosen them and their descendants out of all your tribes to stand and minister in the LORD’s name always.