Exodus 17:3, 6

But the people were very thirsty for water, so they grumbled against Moses. They said, “Why did you bring us out of Egypt? Was it to kill us, our children, and our farm animals with thirst?”

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.