Numbers 21:35
So they smote him, and his sons, and all his people, until there was none left him alive: and they possessed his land. So they smote him, and his sons, and all his people, until there was none left him alive: and they possessed his land.
Israel smote Og, his sons, and all his people until there was none left alive, and possessed his land in complete victory. The defeated king was Og, king of Bashan, and the land taken was the rich territory of Bashan. The same destruction is described as Israel destroying the Amorites and taking possession of their land, proving Israel to be a powerful people.
The victory fulfilled God's promise to deliver Og and his people into Israel's hand, despite their great strength and fortified country. The triumph came as Israel obeyed God's command and advanced under Moses' leadership with the divine presence in the cloudy pillar and the ark, in contrast to the earlier defeat caused by acting against God's command. The triumph gave Israel renewed assurance that God was with them. It showed that those who defied God were powerless against Him, and that God was protecting Israel.
After this victory Israel moved forward and encamped in the plains of Moab on this side of Jordan by Jericho. These victories over the two kings before the Jordan crossing, together with the miraculous crossing, filled the surrounding nations with terror. When Balak king of the Moabites and all Moab learned of the destruction, they were exceedingly terrified and in trouble.