
Amalek defeated EXO 17:11
Amalek attacks the stragglers at Rephidim, and Joshua is sent out to fight while Moses climbs the hill with the staff of God in his hand. As long as his hands are raised Israel prevails, and when they fall Amalek prevails. His hands grow heavy, so Aaron and Hur put a stone under him and hold his arms up on either side until the sun goes down. The victory belongs to the man on the hill as much as to the men in the valley.
The passage
EXO 17:11 · Read the passage9And Moses said unto Joshua, Choose us out men, and go out, fight with Amalek: to morrow I will stand on the top of the hill with the rod of God in mine hand. {Joshua: called Jesus}
10So Joshua did as Moses had said to him, and fought with Amalek: and Moses, Aaron, and Hur went up to the top of the hill.
11And it came to pass, when Moses held up his hand, that Israel prevailed: and when he let down his hand, Amalek prevailed.
12But Moses' hands {were} heavy; and they took a stone, and put {it} under him, and he sat thereon; and Aaron and Hur stayed up his hands, the one on the one side, and the other on the other side; and his hands were steady until the going down of the sun.
13And Joshua discomfited Amalek and his people with the edge of the sword.
14And the LORD said unto Moses, Write this {for} a memorial in a book, and rehearse {it} in the ears of Joshua: for I will utterly put out the remembrance of Amalek from under heaven.
15And Moses built an altar, and called the name of it Jehovahnissi: {Jehovahnissi: that is, The LORD my banner}
The place

Rephidim was a crucial encampment site in the wilderness where the Israelites camped during their journey from Egypt to Mount Sinai. It was here that Moses struck the rock to provide water for the thirsty people, and where Joshua led Israel's first military victory against the Amalekites while Moses held up his hands in prayer.