David did what God told him to do. So David and his men defeated the Philistine army. They killed Philistine soldiers all the way from the town of Gibeon to the town of Gezer.
The Lord will fight as he did at Mount Perazim. He will be angry as he was in Gibeon Valley. He will do what he must do. It will be what some stranger should do, but he will finish his work. Yes, this is a stranger’s job.
But the Ephraimites were not able to force the Canaanites to leave the town of Gezer. So the Canaanites still live among the Ephraimites today, although they did become slaves of the Ephraimites.