Numbers 1:54

And the children of Israel did according to all the Lord
commanded Moses
Pitched their tents by their own camps and standards; did not come near the tabernacle but kept at a proper distance from it, and did not meddle with things they had no concern, with, and which were peculiar to the Levites:

so they did;
which is repeated to show how readily, punctually, and perfectly they observed the command of God with respect to this affair.