John Gill Bible Commentary

That is, if they would, as Aben Ezra observes; for though they had manna daily, yet if they would they might buy other food when they had an opportunity, as they would now have of Edom; but then they were not to take it by force or stealth, but pay for it, which they were able to do. The same writer observes, that some read the words with an interrogation, "shall ye buy meat?" no, there is no need of it; for the Lord had blessed them with a sufficiency of it: and ye shall also buy water of them for money; that ye may drink; which was usual in those hot countries; See Gill on Num 20:19 or dig water (y) that is, pay for digging of wells for water, or buy water out of wells dug in the land of Edom. Jarchi says in maritime places they express buying by this word, and so it is used in the Arabic language; See Gill on Hos 3:2. (y) "fodietis", Montanus.