Jamieson, Fausset and Brown on Matthew 22:7

7. But when the king--the Great God, who is the Father of our Lord Jesus Christ.

heard thereof, he was wroth--at the affront put both on His Son, and on Himself who had deigned to invite them.

and he sent forth his armies--The Romans are here styled God's armies, just as the Assyrian is styled "the rod of His anger" (Is 10:5), as being the executors of His judicial vengeance.

and destroyed those murderers--and in what vast numbers did they do it!

and burned up their city--Ah! Jerusalem, once "the city of the Great King" (Psa 48:2), and even up almost to this time (Mt 5:35); but now it is "their city"--just as our Lord, a day or two after this, said of the temple, where God had so long dwelt, "Behold your house is left unto you desolate" (Mt 23:38)! Compare Lu 19:43, 44.