Exodus 17:3 (KJV)

And all the congregation of the children of Israel journeyed from the wilderness of Sin, after their journeys, according to the commandment of the Lord, and pitched in Rephidim: and there was no water for the people to drink.

Wherefore the people did chide with Moses, and said, Give us water that we may drink. And Moses said unto them, Why chide ye with me? wherefore do ye tempt the Lord?

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

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

And the Lord said unto Moses, Go 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.