Exodus 17:5-6

The LORD said to Moses, “Go ahead of the people, and take some of the elders of Israel with you. Carry with you the walking stick that you used to strike the Nile River. Now go! I will stand in front of you on a rock at Mount Sinai. Hit that rock with the stick, and water will come out of it so that the people can drink.” Moses did these things as the elders of Israel watched.