Judges 11:15

Israel took not away. Jephthah refuted the king of Ammon’s statements. He showed that the Ammonites, and the Moabites, who seemed to be united with them in their claims against Israel, had no legal claim to the territory between the Amon and the Jabbok. To prove his point he described in detail what had taken place when the Israelites took over that country. They had captured the land from Sihon, king of the Amorites, and they were not willing to discuss who had been the previous owners.

Land of Moab. Throughout his denial, Jephthah grouped the Moabites and the Ammonites together, as if they were one people. In v. 24 Chemosh, who was the god of the Moabites, is called the god of the king of Ammon. From this it has been thought that at this time the king of Ammon had perhaps gained control over Moab, either by force of arms or intermarriage, so that the one king ruled over both countries. The national deity of Ammon was Milcom, or Molech (see on Lev. 18:21).