Numbers 20:7

Why have you made us to come up out of Egypt, to bring us in to this evil place? It is no place of seed, or of figs, or of vines, or of pomegranates; neither is there any water to drink.

Moses and Aaron went from the presence of the assembly to the door of the Tent of Meeting, and fell on their faces: and the glory of Yahweh appeared to them.

Take the rod, and assemble the congregation, you, and Aaron your brother, and speak to the rock before their eyes, that it give forth its water; and you shall bring forth to them water out of the rock; so you shall give the congregation and their livestock drink.

Moses took the rod from before Yahweh, as he commanded him.