John Gill Commentary Numbers 4:1

"And Jehovah spake unto Moses and unto Aaron, saying," — Numbers 4:1 (ASV)

And the Lord spoke to Moses, and to Aaron
After they had taken the number of the Levites, and made an exchange of the firstborn of Israel for them; and now they are ordered to number them a second time, and take out from them such as were fit for service:

saying ;
as follows.