Numbers 8:13 (BSB)

You are to have the Levites stand before Aaron and his sons and then present them before the LORD as a wave offering.

From Numbers 8. Also in the ESV.

Commentary on Numbers 8:13

• Matthew Henry (Presbyterian), Matthew Henry's Complete Commentary on Numbers 8:5-26: We read before of the separating of the Levites from among the children of Israel when they were numbered, and the numbering of them by themselves (Num 3:6, Num 3:15), that they might be employed in the service of the tabernacle. Now here we have directions given for their solemn ordination (Num 8:6), and the performance of it, Num 8:20.
• John Gill (Reformed Baptist), Exposition of the Old and New Testaments on Numbers 8:13: And thou shalt set the Levites before Aaron, and before his sons,.... After atonement was made for them, as Aben Ezra observes; then they were presented to Aaron and his sons, to whom they were given to he their ministers, and assistants to them: and offer them for an offering unto the Lord: or, and "waved them", &c.
• Keil & Delitzsch (Lutheran), Biblical Commentary on the Old Testament on Numbers 8:12-19: Num 8:12-19 The Levites were then to close this transfer of themselves to the Lord with a sin-offering and burnt-offering, in which they laid their hands upon the sacrificial animals. By this imposition of hands they made the sacrificial animals their representatives, in which they presented their own bodies to the Lord as a living sacrifice well-pleasing to Him.