We have shot at them; Heshbon is perished even unto Dibon, and we have laid them waste even unto Nophah, which reacheth unto Medeba.

Wesley's Notes

21:30 Though you feeble Moabites, and your God too, could not resist Sihon, we Israelites, by the help of our God, have shot, with success and victory, at them, at Sihon and his Amorites. Heshbon - The royal city of Sihon, and by him lately repaired, Is perished - Is taken away from Sihon, and so is all his country, even as far as Dibon.

Matthew Henry's Concise Commentary

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.