Numbers 3:6-9

3:6 “Bring the tribe of Levi near, and present them before Aaron the priest, that they may serve him. 3:7 They are responsible for his needs and the needs of the whole community before the tent of meeting, by attending to the service of the tabernacle. 3:8 And they are responsible for all the furnishings of the tent of meeting, and for the needs of the Israelites, as they serve in the tabernacle. 3:9 You are to assign the Levites to Aaron and his sons; they will be assigned exclusively to him out of all the Israelites.

Numbers 8:6-14

8:6 “Take the Levites from among the Israelites and purify them. 8:7 And do this to them to purify them: Sprinkle water of purification on them; then have them shave all their body and wash their clothes, and so purify themselves. 8:8 Then they are to take a young bull with its grain offering of fine flour mixed with olive oil; and you are to take a second young bull for a purification offering. 8:9 You are to bring the Levites before the tent of meeting and assemble the entire community of the Israelites. 8:10 Then you are to bring the Levites before the Lord, and the Israelites are to lay their hands on the Levites; 8:11 and Aaron is to offer the Levites before the Lord as a wave offering from the Israelites, that they may do the work of the Lord. 8:12 When the Levites lay their hands on the heads of the bulls, offer the one for a purification offering and the other for a whole burnt offering to the Lord, to make atonement for the Levites. 8:13 You are to have the Levites stand before Aaron and his sons, and then offer them as a wave offering to the Lord. 8:14 And so you are to separate the Levites from among the Israelites, and the Levites will be mine.

Numbers 18:2-6

18:2 “Bring with you your brothers, the tribe of Levi, the tribe of your father, so that they may join with you and minister to you while you and your sons with you are before the tent of the testimony. 18:3 They must be responsible to care for you and to care for the entire tabernacle. However, they must not come near the furnishings of the sanctuary and the altar, or both they and you will die. 18:4 They must join with you, and they will be responsible for the care of the tent of meeting, for all the service of the tent, but no unauthorized person may approach you. 18:5 You will be responsible for the care of the sanctuary and the care of the altar, so that there will be no more wrath on the Israelites. 18:6 I myself have chosen your brothers the Levites from among the Israelites. They are given to you as a gift from the Lord, to perform the duties of the tent of meeting.

Deuteronomy 10:8

10:8 At that time the Lord set apart the tribe of Levi to carry the ark of the Lord’s covenant, to stand before the Lord to serve him, and to formulate blessings in his name, as they do to this very day.