Exodus 17:6

6Behold, I will stand before you there on the rock at 17:6 Horeb may refer to the mountain range of which Sinai is an individual mountain.Horeb; there you shall strike the rock, and water will come out of it, so that the people may [have something to] drink.” And Moses did so in the sight of the elders of Israel. [1 Cor 10:4]