Numbers 18:21-24

21See, I have given the Levites all the tithes in Israel for an inheritance, for their service which they perform – the service of the tent of meeting.

22No longer may the Israelites approach the tent of meeting, or else they will bear their sin and die.

23But the Levites must perform the service of the tent of meeting, and they must bear their iniquity. It will be a perpetual ordinance throughout your generations that among the Israelites the Levites have no inheritance.

24But I have given to the Levites for an inheritance the tithes of the Israelites that are offered to the Lord as a raised offering. That is why I said to them that among the Israelites they are to have no inheritance.”