Numbers 18:21-32
21 “Look, I have given the Levites every tenth in Israel as an inheritance in return for the work they do, the work of the tent of meeting.
22 The Israelites must never again come near the tent of meeting, or they will incur guilt and die.
23 The Levites will do the work of the tent of meeting, and they will bear the consequences of their sin. The Levites will not receive an inheritance among the Israelites;(A) this is a permanent statute throughout your generations.
24 For I have given them the tenth that the Israelites present to the Lord as a contribution for their inheritance. That is why I told them that they would not receive an inheritance among the Israelites.”
25 The Lord instructed Moses,
26 “Speak to the Levites and tell them: When you receive from the Israelites the tenth that I have given you as your inheritance, you must present part of it as an offering to the Lord—a tenth of the tenth.
27 Your offering will be credited to you as if it were your grain from the threshing floor or the full harvest from the winepress.
28 You are to present an offering to the Lord from every tenth you receive from the Israelites. Give some of it to Aaron the priest as an offering to the Lord.
29 You must present the entire offering due the Lord from all your gifts. The best part of the tenth(B) is to be consecrated.
30 “Tell them further: Once you have presented the best part of the tenth, and it is credited to you Levites as the produce of the threshing floor or the winepress,
31 then you and your household may eat it anywhere. It is your wage in return for your work at the tent of meeting.
32 You will not incur guilt because of it once you have presented the best part of it, but you must not defile the Israelites’ holy offerings, so that you will not die.”