Numbers 18:21-30

21See, I have given all the tithes in Israel to the sons of Levi as an inheritance in return for all the work of the service they are doing in the Tent of Meeting.

22From now on, Bnei-Yisrael must never trespass the Tent of Meeting, or they will bear the consequences of their sin and die.

23The Levites will perform the service of the Tent of Meeting. They will bear the responsibility for their iniquity. It is a permanent ordinance throughout your generations. So among Bnei-Yisrael they are to receive no inheritance.

24For I have given the tithes that Bnei-Yisrael present to Adonai as an offering to the Levites as an inheritance. That is why I said they would receive no inheritance among Bnei-Yisrael.”

25Adonai spoke to Moses saying,

26“Speak now to the Levites and say to them: When you receive from Bnei-Yisrael the tithe which I have given to you as your inheritance, you are then to offer to Adonai a tithe of that tithe.

27Your offering will be reckoned as grain from the threshing floor or the fullness of the winepress.

28Thus you will also present an offering to Adonai from all your tithes that you receive from Bnei-Yisrael, and from that you are to give Adonai’s portion to Aaron the kohen.

29From all your gifts that you receive, you are to present the best and holiest from them as Adonai’s portion.

30“Say to them: When you present the best part, it will be reckoned to the Levites as the produce of the threshing floor and of the winepress.