Exodus 17:2-6

2Wherefore the people strove with Moses, and said, Give us water that we may drink. And Moses said unto them, Why strive ye with me? wherefore do ye tempt the LORD?

3And the people thirsted there for water; and the people murmured against Moses, and said, Wherefore hast thou brought us up out of Egypt, to kill us and our children and our cattle with thirst?

4And Moses cried unto the LORD, saying, What shall I do unto this people? they be almost ready to stone me.

5And the LORD said unto Moses, Pass on before the people, and take with thee of the elders of Israel; and thy rod, wherewith thou smotest the river, take in thine hand, and go.

6Behold, 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.