26 For Heshbon was the city of Sihon the king of the Amorites, who had fought against the former king of Moab and taken all his land out of his hand, as far as the Arnon. 27 Therefore the ballad singers say, "Come to Heshbon, let it be built, let the city of Sihon be established. 28 For fire went forth from Heshbon, flame from the city of Sihon. It devoured Ar of Moab, the lords of the heights of the Arnon. 29 Woe to you, O Moab! You are undone, O people of Chemosh! He has made his sons fugitives, and his daughters captives, to an Amorite king, Sihon. 30 So their posterity perished from Heshbon, as far as Dibon, and we laid waste until fire spread to Med'eba."

Matthew Henry's Commentary on Numbers 21:26-30

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.