23 But King Sihon refused to let them cross his territory. Instead, he mobilized his entire army and attacked Israel in the wilderness, engaging them in battle at Jahaz. 24 But the Israelites slaughtered them with their swords and occupied their land from the Arnon River to the Jabbok River. They went only as far as the Ammonite border because the boundary of the Ammonites was fortified. 25 So Israel captured all the towns of the Amorites and settled in them, including the city of Heshbon and its surrounding villages. 26 Heshbon had been the capital of King Sihon of the Amorites. He had defeated a former Moabite king and seized all his land as far as the Arnon River.
Matthew Henry's Commentary on Numbers 21:23-26
Commentary on Numbers 21:21-35
(Read Numbers 21:21-35)
Sihon went with his forces against Israel, out of his own borders, without provocation, and so ran upon his own ruin. The enemies of God's church often perish by the counsels they think most wisely taken. Og, king of Bashan, instead of being warned by the fate of his neighbours, to make peace with Israel, makes war with them, which proves in like manner his destruction. Wicked men do their utmost to secure themselves and their possessions against the judgments of God; but all in vain, when the day comes on which they must fall. God gave Israel success, while Moses was with them, that he might see the beginning of the glorious work, though he must not live to see it finished. This was, in comparison, but as the day of small things, yet it was an earnest of great things. We must prepare for fresh conflicts and enemies. We must make no peace or truce with the powers of darkness, nor even treat with them; nor should we expect any pause in our contest. But, trusting in God, and obeying his commands, we shall be more than conquerors over every enemy.