Numbers 8:9-11

Amplified Bible

⁹ You shall present the Levites before the Tent of Meeting (tabernacle), and you shall also assemble the whole congregation of the children of Israel, ¹⁰ and present the Levites before the Lord, and the Israelites shall lay their hands on the Levites. ¹¹ Aaron shall ^[a]present the Levites before the Lord as a wave offering from the Israelites, so that they may perform the service of the Lord.