Behold, I will stand there before you by the rock at Horeb. And when you strike the rock, water will come out of it for the people to drink.” So Moses did this in the sight of the elders of Israel.
Jewish Publication Society of America Version (JPS1917) - Exodus 17:6 >Behold, I will stand before thee there upon the rock in Horeb; and thou shalt smite the rock, and there shall come water out of it, that the people may drink.' And Moses did so in the sight of the elders of Israel.