Numbers 18:23-24

23But the Levite, he shall perform the service of the tent of meeting, and they shall bear their iniquity: it is an everlasting statute throughout your generations. And among the children of Israel shall they possess no inheritance;

24for I have given for an inheritance to the Levites the tithes of the children of Israel, which they offer as a heave-offering to Jehovah; therefore I have said of them, They shall possess no inheritance among the children of Israel.