1 Samuel 14:21-23

21Those Hebrews who had previously been with the Philistines and had gone up with them to their camp went over to the Israelites who were with Saul and Jonathan. 22When all the Israelites who had hidden in the hill country of Ephraim heard that the Philistines were on the run, they joined the battle in hot pursuit.

23So on that day the LORD saved Israel, and the battle moved on beyond Beth Aven.