כִּי־אֵשׁ֙ יָֽצְאָ֣ה מֵֽחֶשְׁבּ֔וֹן לֶהָבָ֖ה מִקִּרְיַ֣ת סִיחֹ֑ן אָֽכְלָה֙ עָ֣ר מוֹאָ֔ב בַּעֲלֵ֖י בָּמ֥וֹת אַרְנֹֽן׃
Poiché un fuoco è spento da Heshbon, una fiamma proveniente dalla città di Sihon; Ha divorato Ar di Moab, i signori degli alti luoghi di Arnon.
Rashi on Numbers
כי אש יצאה מחשבון FOR A FIRE WILL GO FORTH FROM HESHBON after Sihon captures it,
Rashbam on Numbers
ער מואב, the capital of the land of Moav was called Or.
Rabbeinu Bahya
כי אש יצאה מחשבון, ”for a fire has come forth from Cheshbon.” This is an allusion to Moabites who had dwelled in Chesbon and commenced a revolution against the local king.