The Presence of the Lord appeared to them, and the Lord spoke to Moses, saying, "You and your brother Aaron take the rod and assemble the community, and before their very eyes order the rock to yield its water. Thus you shall produce water for them from the rock and provide drink for the congregation and their beasts."
Moses took the rod from before the Lord, as He had commanded him. Moses and Aaron assembled the congregation in front of the rock; and he said to them, "Listen, you rebels, shall we get water for you out of this rock?" And Moses raised his hand and struck the rock twice with his rod. Out came copious water, and the community and their beasts drank.
But the Lord said to Moses and Aaron, "Because you did not trust Me enough to affirm My sanctity in the sight of the Israelite people, therefore you shall not lead this congregation into the land that I have given them." Those are the Waters of Meribah--meaning that the Israelites quarrelled with the Lord--through which He affirmed His sanctity.