Numbers 8:15, 19

“Make the Levites pure, and present them as an offering so that they may come to work at the Meeting Tent.

From all the Israelites I have given the Levites to Aaron and his sons so that they may serve the Israelites at the Meeting Tent. They will help remove the Israelites’ sins so they will belong to the LORD and so that no disaster will strike the Israelites when they approach the Holy Place.”