The Philistines put themselves in array against Israel: and when they joined battle, Israel was struck before the Philistines; and they killed of the army in the field about four thousand men.
Perhaps the elders of Israel remembered that in Joshua’s conquest of Jericho, the ark played a very important and visible part in the victory (Joshua 6:2-20). Nevertheless, back then the people trusted in Yahweh, not in the ark as a talisman (good luck charm). The custom of taking idols into battle so their gods would deliver them was common among ancient warriors (cf. 2 Samuel 5:21; 1 Chronicles 14:12). Obviously the Israelites were wrong in thinking that the presence of the ark would guarantee success.