Numbers 3:6

3 These are the names of the sons of Aaron, the priests that were anointed, whom he consecrated to minister in the priest’s office.

4 And Nadab and Abihu died before Jehovah, when they offered strange fire before Jehovah, in the wilderness of Sinai, and they had no children; and Eleazar and Ithamar ministered in the priest’s office in the presence of Aaron their father.

5 And Jehovah spake unto Moses, saying,

6 Bring the tribe of Levi near, and set them before Aaron the priest, that they may minister unto him.

7 And they shall keep his charge, and the charge of the whole congregation before the tent of meeting, to do the service of the tabernacle.

8 And they shall keep all the furniture of the tent of meeting, and the charge of the children of Israel, to do the service of the tabernacle.

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