Numbers 21:32

And Moses sent to spy out Jaazer, and they took the villages thereof, and drove out the Amorites that were there.

The verse records the taking of Jaazer and its villages, with the driving out and destruction of the Amorites who were there and the taking possession of their land, as part of the successful advance against the Amorite kingdoms in which Israel slew two kings east of the Jordan before entering Canaan. Those victories came as Israel followed God's command and went forward with Moses and the signs of God's presence leading them. They showed God's power and proved that the Lord fought for Israel.

The victory proved Israel to be a powerful people who could not be harmed while faithful to God, a fact made clear to Balaam. When Israel afterward pitched in the plains of Moab by Jordan near Jericho, Balak and all Moab learned of the victory and were exceedingly terrified. Together with the miraculous passage over the swollen Jordan, the victory melted the hearts of the kings of the Amorites and the Canaanites with fear and filled all the surrounding nations with great terror.