Verse 28. - There is a fire gone out of Heshbon. This must refer to the war-fire which the Amorites kindled from Heshbon when they made it the capital of the new kingdom. Ar Moab and the (northern) heights of Arnon were the furthest points to which their victory extended.

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.For there is a fire gone out of Heshbon,.... Not before, but after Sihon had subdued it, as Jarchi observes; and is to be understood of his soldiers going out from thence, and making desolations in the adjacent parts, like a strong fire, and the fierce flames of it there is no resisting; and so the Jerusalem Targum,"for a people mighty, and burning like fire, are gone out of Heshbon:''see Amos 1:4, a flame from the city of Sihon: which is the same thing in other words, the city of Sihon being Heshbon, and a flame the same with fire; warriors, as both the Targums of Oakelos and Jerusalem interpret it; this seems to be what those composers undertook in their poetical way to foretell would be the case in future times; concluding, from the conquests already made, that they would be extended much further, and that no opposition could hinder:

it hath consumed Ar of Moab; the metropolis of the country of Moab, that is, they were as sure of it, and endeavoured to make the people by these their compositions as confident of it, that this city would fall into the hands of their armies, and be destroyed, as if it was already done; otherwise it does not appear that it ever was taken out of the hands of the Moabites, until taken by the Assyrians or Chaldeans; of this city See Gill on Isaiah 15:1.

and the lords of the high places of Arnon; who had the government of the high, strong, and fortified places all along the river Arnon; these it is suggested would be conquered by the Amorites; all the three Targums interpret it of the priests and worshippers in the temples, and at the altars of the idols in Arnon; and it may be rendered, "the Baals of the high places of Arnon", as if the gods of those places should fall into the victors' hands; and which seems to have some confirmation from what follows; and it may be observed, that in these parts there were some places called Bamoth Baal, or the high places of Baal, see Numbers 22:41, and Beth Baal Meon, which has its name from its being the temple and habitation of Baal, Joshua 13:17.