Numbers 18:22-23

The Israelites shall never again approach the Tent of Meeting [the covered sanctuary, the Holy Place, and the Holy of Holies], or they [who do] will incur sin and die. Only the Levites shall perform the service of the Tent of Meeting (tabernacle), and they shall bear their iniquity; it shall be a statute forever throughout your generations, that the Levites shall have no inheritance [of land] among the children of Israel.