And after that shall the Levites go in... — i.e., into the court of the Tabernacle to keep watch there, and to assist the priests at the altar of burnt-offering, and to take down and set up the Tabernacle as occasion might require.
Related Commentaries of Numbers 8:15
Numbers 8:15
15 And after that shall the Levites go in to do the service of the tabernacle of the congregation: and thou shalt cleanse them, and offer them for an offering.