Numbers 18:21-29

21“To the sons of Levi, behold, I have given all the 1tithe in Israel for an inheritance, in return for their service which they perform, the service of the tent of meeting. 222The sons of Israel shall not come near the tent of meeting again, or they will bear sin and die. 23Only the Levites shall perform the service of the tent of meeting, and they shall 3bear their iniquity; it shall be a perpetual statute throughout your generations, and among the sons of Israel 4they shall have no inheritance. 24For the tithe of the sons of Israel, which they offer as an offering to the Lord, I have given to the Levites for an inheritance; therefore I have said concerning them, ‘5They shall have no inheritance among the sons of Israel.’”

25Then the Lord spoke to Moses, saying, 26“Moreover, you shall speak to the Levites and say to them, ‘When you take from the sons of Israel 6the tithe which I have given you from them for your inheritance, then you shall present an offering from it to the Lord, a 7tithe of the tithe. 27Your offering shall be reckoned to you as the grain from the threshing floor or the full produce from the wine vat. 28So you shall also present an offering to the Lord from your tithes, which you receive from the sons of Israel; and from it you shall give the Lord’s offering to Aaron the priest. 29Out of all your gifts you shall present every offering due to the Lord, from all the 8best of them, 9the sacred part from them.’