Numbers 3:6-16

6“Bring the tribe of Levi and present them to Aaron the priest to assist him. 7They are to perform duties for him and for the whole congregation before the Tent of Meeting, attending to the service of the tabernacle. 8They shall take care of all the furnishings of the Tent of Meeting and fulfill obligations for the Israelites by attending to the service of the tabernacle.

9Assign the Levites to Aaron and his sons; they have been given exclusively to him1 from among the Israelites. 10So you shall appoint Aaron and his sons to carry out the duties of the priesthood; but any outsider who approaches the tabernacle must be put to death.”

11Again the LORD spoke to Moses, saying, 12“Behold, I have taken the Levites from among the children of Israel in place of every firstborn Israelite from the womb. The Levites belong to Me, 13for all the firstborn are Mine. On the day I struck down every firstborn in the land of Egypt, I consecrated to Myself all the firstborn in Israel, both man and beast. They are Mine; I am the LORD.”

14Then the LORD spoke to Moses in the Wilderness of Sinai, saying, 15“Number the Levites by their families and clans. You are to count every male a month old or more.”

16So Moses numbered them according to the word of the LORD, as he had been commanded.