Numbers 18:4-6

Amplified Bible

⁴ They shall join you and attend to the duties of the Tent of Meeting—all the service of the tent—and no stranger [no layman, anyone who is not a Levite] may approach you [and your sons]. ⁵ So you shall attend to the duties of the sanctuary and the duties of the altar [of burnt offering and the altar of incense], so that there will no longer be wrath on the Israelites [as with Korah, Dathan, and Abiram].^{(A) 6} Behold, I Myself have taken your fellow Levites from among the sons of Israel; they are a gift to you, given (dedicated) to the Lord, to do the service for the Tent of Meeting (tabernacle).