Judges 11:24
Wilt not thou possess that which Chemosh thy god giveth thee to possess? So whomsoever the LORD our God shall drive out from before us, them will we possess. Wilt not thou possess that which Chemosh thy god giveth thee to possess? So whomsoever the LORD our God shall drive out from before us, them will we possess.
Jephthah was raised up by God as a deliverer to lead Israel in war against the Ammonites. This deliverance came after Israel had endured eighteen years of oppression under Ammonite power. The statement about Chemosh giving possession and the Lord driving out nations belongs to that account of Jephthah's confrontation with Ammon.