The king of the children of Ammon answered to the messengers of Jephthah, Because Israel took away my land, when he came up out of Egypt, from the Arnon even to the Jabbok, and to the Jordan: now therefore restore those [lands] again peaceably.
Third, Jephthah appealed logically that Ammon had not tried to take the land she now claimed for 300 years. If she had a legitimate claim on it, she should have tried to secure it long ago (Judges 11:26).