King James Bible
"After he had slain Sihon the king of the Amorites, which dwelt in Heshbon, and Og the king of Bashan, which dwelt at Astaroth in Edrei:"
This references Israel's decisive victory over Sihon, whose territory east of the Jordan became the inheritance of Reuben and Gad. The defeat of this Amorite king marked the beginning of Israel's conquest of the Promised Land, demonstrating God's power to fulfill His promises despite formidable opposition. Og was the last of the Rephaim giants, and his defeat removed the final major obstacle before crossing the Jordan. These twin victories over powerful kings established Moses' authority and God's faithfulness, providing the historical context for Moses' farewell address to Israel.