Must we fetch you water out of this rock? — In the case of the former miracle at Rephidim the rock is spoken of only under the Hebrew word zur (Exodus 17:6). Throughout the present narration the rock is invariably spoken of under the word sela. In Psalms 78:15-16, where reference appears to be made to both miracles, both words are used.
Related Commentaries of Numbers 20:10
Numbers 20:10
10 And Moses and Aaron gathered the congregation together before the rock, and he said unto them, Hear now, ye rebels; must we fetch you water out of this rock?