Children of Israel said unto him, i.e. their messengers replied unto them what here follows. I will pay for it; for water was a scarce commodity in those parts.
Related Commentaries of Numbers 20:19
Numbers 20:19
19 And the children of Israel said unto him, We will go by the high way: and if I and my cattle drink of thy water, then I will pay for it: I will only, without doing any thing else, go through on my feet.