Numbers 18:1-7 - Provision For The Priesthood
1 And the LORD said unto Aaron, "Thou and thy sons and thy father's house with thee, shall bear the fault of that which is done amiss in the holy place. And thou and thy sons with thee, shall bear the fault of that which is done amiss in your priesthood. 2 And thy brethren also, the tribe of Levi, the tribe of thy father take with thee, and let them be joined unto thee and minister unto thee. And thou and thy sons with thee shall minister before the tabernacle of witness. 3 And let them wait upon thee and upon all the tabernacle: only let them not come nigh the holy vessels and the altar, that both they and ye also die not. 4 And let them be by thee and wait on the tabernacle of witness, and on all the service of the tabernacle, and let no stranger come nigh unto you.
5 Wait therefore upon the holy place and upon the altar, that there fall no more wrath upon the children of Israel: 6 behold, I have taken your brethren the Levites from among children of Israel, to be yours, as gifts given unto the LORD to do the service of the tabernacle of witness. 7 And see that both thou and thy sons with thee take heed unto your priests' office, in all things that pertain unto the altar and within the veil. And see that ye serve, for I have given your priests' office unto you for a gift to do service: and the stranger that cometh nigh, shall die."