Numbers 8:22

And after that the Levites went in to do their service in the tent of meeting before Aaron and his sons ; as the Lord had commanded Moses concerning the Levites , so they did to them.

After that, the Levites came to do their work at the tent of meeting under the supervision of Aaron and his sons. They did with the Levites just as the Lord commanded Moses.

And after that went the Levites in to do their service in the tabernacle of the congregation before Aaron, and before his sons : as the Lord had commanded Moses concerning the Levites, so did they unto them.