Numbers 18:8

The Portion of the Priests

18:8 The Lord spoke to Aaron, “See, I have given you the responsibility for my raised offerings; I have given all the holy things of the Israelites to you as your priestly portion and to your sons as a perpetual ordinance.

Numbers 18:23

18:23 But 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.

Numbers 19:21

19:21 “‘So this will be a perpetual ordinance for them: The one who sprinkles the water of purification must wash his clothes, and the one who touches the water of purification will be unclean until evening.