The Amalekites came and attacked the Israelites at Rephidim. Moses said to Joshua, “Choose some of our men and go out to fight the Amalekites. Tomorrow I will stand on top of the hill with the staff of God in my hands.”
So Joshua fought the Amalekites as Moses had ordered, and Moses, Aaron and Hur went to the top of the hill. As long as Moses held up his hands, the Israelites were winning, but whenever he lowered his hands, the Amalekites were winning. When Moses’ hands grew tired, they took a stone and put it under him and he sat on it. Aaron and Hur held his hands up—one on one side, one on the other—so that his hands remained steady till sunset. So Joshua overcame the Amalekite army with the sword.
Then the Lord said to Moses, “Write this on a scroll as something to be remembered and make sure that Joshua hears it, because I will completely blot out the name of Amalek from under heaven.”
Moses built an altar and called it The Lord is my Banner. He said, “Because hands were lifted up against the throne of the Lord, the Lord will be at war against the Amalekites from generation to generation.”
In the desert, Israel faced existential threats on all sides. Hunger. Thirst. Disease. Hostile armies. During their time in the desert, however, we see that Israel’s God is a god who provides relief from all these threats. He provides manna and quail to curb hunger, water from a rock and from a bitter spring made pure to quench thirst, laws that were prescient examples of public health to prevent disease (e.g., don’t eat shellfish that you can’t refrigerate), and here, protection from the hostile Amalekite army.
Whenever God involves a human being in a miracle, such as Moses’ pivotal role in this miraculous victory in battle, our first question should be “Why?” After all, we believe God is omnipotent. That means he can do anything in any way. There are a thousand more efficient ways that God could have defeated the Amalekites. He could have just made them magically disappear. He could have caused the earth to open and swallow them up. He could have caused them all to go blind and let the Israelite soldiers go in and mop them up. And so on.
God accomplishes his purposes no matter how he goes about them, so we can only conclude, then, that the particular methods of miraculous action that he selects are designed to be instructive to some audience. Why did he put the constraint upon this miracle that the Israelites would only prevail in battle as long as Moses’ arms remained uplifted?
I think there are at least two main reasons. First, God wanted to demonstrate to Moses, and by extension, Israel, that it is only by God’s miraculous and omnipresent power that battles are won. Moses’ hands were to be uplifted, the traditional posture for prayer at the time, if Israel was to be victorious. In the language of modern American church conventions, this would be like God telling us that a battle would only be won as long as our hands were folded, heads bowed, and eyes closed. As David says when about to face Goliath in 1 Samuel 17:47, “All those gathered here will know that it is not by sword or spear that the Lord saves; for the battle is the Lord’s…” and as Jahaziel, inspired by the Spirit of the Lord, echoes in 2 Chronicles 20:15, “…the battle is not yours, but God’s.” The fact that Moses’ posture of prayerfulness has some sort of mysterious causal effect on the battle’s outcome points to an immediate divine intervention, and thus discredits anyone who might claim that the battle was won merely by the strength or training of Israel’s fighting men.
The second reason for this constraint is that God is trying to teach Moses about the importance of community and interdependence. God knows that telling Moses to lift his arms up for a whole day is an impossible task without help. Extend your arms out straight, parallel to the ground, and hold them there. I start to feel a burn after just a minute or two; I don’t know about you. Even if thousands of men’s lives were at stake, I know I couldn’t last all day like that. So God is saying to Moses, and also to us, that we simply cannot do it alone. Not only do we need God–we also need each other. We each have our own Aaron and Hur to support us when our strength is failing. That’s what the people of God are supposed to be for each other. God was giving Moses a sneak preview of the lesson he would learn in Chapter 18, which God speaks through Moses’ father-in-law Jethro: “The work is too heavy for you; you cannot handle it alone” (Exodus 18:17).
There are times where we’re Moses in the story, and we need the support of the people of God if we are to have victory. And there are times where we’re Aaron or Hur in the story, and we need to be there for our brother or sister whose strength is failing and whose hope is waning. By God’s grace, the church is a place where we can just be who we are. Some days we’re Moses; some days we’re Aaron or Hur. But through it all, God is saying that “It is not good for man to be alone” (Genesis 2:18).