Exodus 17:5

17:5 The Lord said to Moses, “Go over before the people; take with you some of the elders of Israel and take in your hand your staff with which you struck the Nile and go.

Exodus 17:9

17:9 So Moses said to Joshua, “Choose some of our men and go out, fight against Amalek. Tomorrow I will stand on top of the hill with the staff of God in my hand.”