"To the Levites I have given every tithe in Israel for an inheritance, in return for their service that they do, their service in the tent of meeting."
Numbers 18:21
See: Notes on Numbers by Thomas L. Constable
Publisher: Constable's Bible Study Notes
See Sermon: Numbers 18:21-19:22 by Skip Heitzig
Publisher: Calvary Church Albuquerque
Info from GetContent.xyz