Deuteronomy 18:3-7

“Now this shall be the priests’ portion from the people, from those who offer a sacrifice, either an ox or a sheep: they shall give the priest the shoulder, the two cheeks, and the stomach.

You shall give him the first fruits of your grain, your new wine, and your oil, and the first fleece of your sheep.

For the Lord your God has chosen him and his sons from all your tribes, to stand to serve in the name of the Lord always.

“Now if a Levite comes from any of your towns throughout Israel where he resides, and he comes whenever he desires to the place which the Lord chooses,

then he shall serve in the name of the Lord his God, like all his fellow Levites who stand there before the Lord.