1 Samuel 14:21-22

²¹Now the Hebrews who had been with the Philistines before that time and who had gone up with them into the camp, even they also turned to be with the Israelites who were with Saul and Jonathan. ²²Likewise, when all the men of Israel who had hid themselves in the hill country of E'phraim heard that the Philistines were fleeing, they too followed hard after them in the battle.