Numbers 18:20-24
20 Then the Lord said to Aaron, “You shall have no inheritance in their land nor own any portion among them; I am your portion and your inheritance among the sons of Israel.
21 “To the sons of Levi, behold, I have given all the tithe in Israel for an inheritance, in return for their service which they perform, the service of the tent of meeting. 22 The sons of Israel shall not come near the tent of meeting again, or they will bear sin and die. 23 Only the Levites shall perform the service of the tent of meeting, and they shall bear their iniquity; it shall be a perpetual statute throughout your generations, and among the sons of Israel they shall have no inheritance. 24 For 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, ‘They shall have no inheritance among the sons of Israel.’”
Numbers 1:47-54
47 The Levites, however, were not numbered among them by their fathers’ tribe. 48 For the Lord had spoken to Moses, saying, 49 “Only the tribe of Levi you shall not number, nor shall you take their census among the sons of Israel. 50 But you shall appoint the Levites over the tabernacle of the testimony, and over all its furnishings and over all that belongs to it. They shall carry the tabernacle and all its furnishings, and they shall take care of it; they shall also camp around the tabernacle. 51 So when the tabernacle is to set out, the Levites shall take it down; and when the tabernacle encamps, the Levites shall set it up. But the layman who comes near shall be put to death.
52 The sons of Israel shall camp, each man by his own camp, and each man by his own standard, according to their armies. 53 But the Levites shall camp around the tabernacle of the testimony, so that there will be no wrath on the congregation of the sons of Israel. So the Levites shall keep charge of the tabernacle of the testimony.” 54 Thus the sons of Israel did; according to all which the Lord had commanded Moses, so they did.