With the ground shaking, the Philistines realized that the Lord was against them. Knowing his power, they wanted to get as far away from the land of Israel as possible. Frightened and panicked, it seemed as if they were willing to even kill their comrades in their efforts to get back home (see Judges 7:22).
20 Then Saul and all the people who were with him rallied and went into the battle. And behold, every Philistine’s sword was against his fellow, and there was very great confusion.