Exodus 17:2-6

So the people quarreled with Moses and said, “Give us water so that we may drink!” And Moses said to them, “Why do you quarrel with me? Why do you test the Lord?”

But the people were thirsty for water there; and they grumbled against Moses and said, “Why is it that you have brought us up from Egypt, to kill us and our children and our livestock with thirst?”

So Moses cried out to the Lord, saying, “What am I to do with this people? A little more and they will stone me!”

Then the Lord said to Moses, “Pass before the people and take with you some of the elders of Israel; and take in your hand your staff with which you struck the Nile, and go.

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