When the Philistines heard the noise of the shout, they said, What means the noise of this great shout in the camp of the Hebrews? They understood that the ark of Yahweh was come into the camp.
The fact that the Israelites suffered a devastating slaughter (Heb. makkah, 1 Samuel 4:10), many times worse than their earlier recent defeat (1 Samuel 4:2), proved that victory did not come from the ark but from the Lord. Defeat was due to sin in the camp, including Hophni and Phinehas’ sin (cf. 1 Samuel 2:25). Israel had suffered defeat at Ai about 300 years earlier for the same reason: sin among the people (Joshua 7:11). Trying to duplicate previous spiritual victories by going through the same procedures is no substitute for getting right with God (cf. Judges 16:20; Matthew 23:25).