Numbers 8:13-14

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 8:24-26

8:24 “This is what pertains to the Levites: At the age of twenty-five years and upward one may begin to join the company in the work of the tent of meeting, 8:25 and at the age of fifty years they must retire from performing the work and may no longer work. 8:26 They may assist their colleagues in the tent of meeting, to attend to needs, but they must do no work. This is the way you must establish the Levites regarding their duties.”

Numbers 18:1-8

Responsibilities of the Priests

18:1 The Lord said to Aaron, “You and your sons and your tribe with you must bear the iniquity of the sanctuary, and you and your sons with you must bear the iniquity of your priesthood.

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. 18:7 But you and your sons with you are responsible for your priestly duties, for everything at the altar and within the curtain. And you must serve. I give you the priesthood as a gift for service; but the unauthorized person who approaches must be put to death.”

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.

Isaiah 66:21

66:21 And I will choose some of them as priests and Levites,” says the Lord.

Jeremiah 33:17-22

33:17 For I, the Lord, promise: “David will never lack a successor to occupy the throne over the nation of Israel. 33:18 Nor will the Levitical priests ever lack someone to stand before me and continually offer up burnt offerings, sacrifice cereal offerings, and offer the other sacrifices.”’”

33:19 The Lord spoke further to Jeremiah. 33:20 “I, Lord, make the following promise: ‘I have made a covenant with the day and with the night that they will always come at their proper times. Only if you people could break that covenant 33:21 could my covenant with my servant David and my covenant with the Levites ever be broken. So David will by all means always have a descendant to occupy his throne as king and the Levites will by all means always have priests who will minister before me. 33:22 I will make the children who follow one another in the line of my servant David very numerous. I will also make the Levites who minister before me very numerous. I will make them all as numerous as the stars in the sky and as the sands which are on the seashore.’”