What does 1 Samuel 4:7 mean?

The Philistines heard the roar of mighty shouts from the Israelite camp and knew something had changed. They badly defeated the Israelites in the first skirmish of this war, but now the Israelites seemed to be celebrating something. In fact, Israel's recently defeated army was roaring in celebration. Then the news came: the ark of the Lord had been brought to the Israelite camp (1 Samuel 4:1–6).

The Philistines take this as terrible news. They believe a god has come into the camp of the Israelites to fight for them. In other words, the Philistines think of the ark of the Lord as a physical manifestation of the god of the Israelites. Because of their own view that idols were actually gods, like the statue of their own god Dagon (1 Samuel 5:2–5), they are sure the arrival of the ark means that Israel's god had arrived to fight for them. How do you fight a god, especially the god of the Israelites (1 Samuel 4:8)? "Woe to us!" they cry. "Nothing like this has ever happened to us!"

The Israelites will soon prove they had also mistaken God's ark as being the source of His power, rather than recalling that God's power comes from Himself. Though He caused His presence to rest over the ark, the ark was not God. It was not where His power came from. He was not contained or manipulated by a physical object.