Numbers 21:24
And Israel smote him with the edge of the sword, and possessed his land from Arnon unto Jabbok, even unto the children of Ammon: for the border of the children of Ammon was strong. And Israel smote him with the edge of the sword, and possessed his land from Arnon unto Jabbok, even unto the children of Ammon: for the border of the children of Ammon was strong.
The verse records Israel's defeat and destruction of Sihon and the Amorites and the taking of his territory and land from the Arnon north to the Jabbok as far as the border of Ammon. That territory had been taken by the Amorites from Moab, and Israel had to cross it on the way to the Jordan. In contrast to Israel's earlier defeat when acting against God's command without Moses, the cloudy pillar, or the ark, in this battle Israel advanced at God's command with Moses and the divine presence leading them and won a complete victory through the Lord's power. That possession could have been gained thirty-eight years earlier if they had trusted Him.
The victory gave Israel rich lands and proved Israel was a powerful people, and it strengthened its confidence while waiting on the border of Canaan. It belongs with the recent victories over Sihon and Og that showed God's power on Israel's behalf and made clear to Balaam how terrible it was for anyone to oppose God. When Israel moved forward and camped in the plains of Moab by Jericho, Balak and all Moab learned of the defeat of the Amorites and were exceedingly terrified.
The slaying of the two kings east of the Jordan before entering Canaan, together with the Lord staying the swollen and impetuous Jordan before the children of Israel, filled the kings of the Amorites and the kings of the Canaanites with melting fear.