Numbers 21:21-35 recounts Israel's request to pass through Sihon's land and the battle — the same event Jephthah summarizes here.

Deuteronomy 2:26-34 gives Moses' version of the Sihon negotiation and conquest — the same story Jephthah retells to the Ammonites.

Deuteronomy 3:1-17 recounts the same conquest of Sihon and Og that Jephthah references here as precedent for Israel's right to the land.

Joshua 13:8-12 lists the same Transjordan territories given to Reuben, Gad, and Manasseh — the land Jephthah claims Israel legitimately held.