Exodus 17:5; Exodus 17:6

5 And the LORD said to Moses, "Pass on before the people, taking with you some of the elders of Israel, and take in your hand the staff with which you struck the Nile, and go.

6 Behold, I will stand before you there on the rock at Horeb, and you shall strike the rock, and water shall come out of it, and the people will drink." And Moses did so, in the sight of the elders of Israel.