John Gill Commentary Numbers 19:1

"And Jehovah spake unto Moses and unto Aaron, saying," — Numbers 19:1 (ASV)

And the Lord spoke to Moses, and to Aaron
Not at this time, after the business of the spies, and the affair of Korah, but before the children of Israel departed from Sinai; and so Aben Ezra observes, that this was spoken in the wilderness of Sinai, when the Lord commanded to put unclean persons out of the camp, and when some were defiled with a dead body, and unfit for the passover, (Numbers 5:2) (9:6) ; and mention is made of the "water of purifying", (Numbers 8:7) ;

saying ;
as follows.