Numbers 3:9

And thou shalt give the Levites unto Aaron and to his sons: they are wholly given unto him out of the children of Israel.

Cross-references

Numbers 8:19 repeats the giving of Levites to Aaron, adding the purpose of atonement and prevention of plague.

Numbers 18:6 echoes the same gift of Levites to Aaron, emphasizing they do the work of the tabernacle.

Numbers 18:7 details the priests' exclusive altar duties, complementing the Levites' supportive role given here.