Numbers 8:20

18 But I have taken the Levites in place of all the firstborn among the sons of Israel.

19 And I have given the Levites as a gift to Aaron and his sons from among the Israelites, to perform the service for the Israelites at the Tent of Meeting and to make atonement on their behalf, so that no plague will come against the Israelites when they approach the sanctuary.”

So Moses, Aaron, and the whole congregation of Israel did with the Levites everything that the LORD had commanded Moses they should do.

21 The Levites purified themselves and washed their clothes, and Aaron presented them as a wave offering before the LORD. Aaron also made atonement for them to cleanse them.

22 After that, the Levites came to perform their service at the Tent of Meeting in the presence of Aaron and his sons. Thus they did with the Levites just as the LORD had commanded Moses.

This was said to Israel at a particular time, so it is wise to read it together with the surrounding text. Do read the surrounding verses too, because the context often says more than a single verse.

Compare

BSB
So Moses, Aaron, and the whole congregation of Israel did with the Levites everything that the LORD had commanded Moses they should do.
KJV
And Moses, and Aaron, and all the congregation of the children of Israel, did to the Levites according unto all that the LORD commanded Moses concerning the Levites, so did the children of Israel unto them.
WEB
Moses, and Aaron, and all the congregation of the children of Israel did so to the Levites. According to all that the LORD commanded Moses concerning the Levites, so the children of Israel did to them.
ASV
Thus did Moses, and Aaron, and all the congregation of the children of Israel, unto the Levites: according unto all that Jehovah commanded Moses touching the Levites, so did the children of Israel unto them.
DARBY
And Moses and Aaron, and all the assembly of the children of Israel, did to the Levites according to all that Jehovah had commanded Moses concerning the Levites: so did the children of Israel to them.
BLB
And Moses and Aaron and all the congregation of the sons of Israel did to the Levites according to all that YHWH commanded Moses concerning the Levites; so the sons of Israel did to them.
ÅB
Og Moses og Aron og hele Israels barns menighet gjorde slik med levittene; aldeles som Herren hadde befalt Moses om levittene, slik gjorde Israels barn med dem.
OTB
Moses, Aron og hele den israelittiske menigheten gjorde med levittene akkurat som Herren hadde befalt Moses.
B1930
Og Moses og Aron og hele Israels barns menighet gjorde således med levittene; aldeles som Herren hadde befalt Moses om levittene, således gjorde Israels barn med dem.

Study notes (Tyndale)

Original text and word study