John Chrysostom

What then did He after these things? Since they were not willing to come, yea and also slew those that came unto them; He burns up their cities, and sent His armies and slew them. And these things He saith, declaring beforehand the things that took place under Vespasian and Titus, and that they provoked the father also, by not believing in Him; it is the father at any rate who was avenging. …

Homily on the Gospel of Matthew 69 ↗

Jerome

But when the king heard this, he was angry. Regarding what was said above: The kingdom of heaven is like a king who prepared a wedding feast and showed acts of mercy. The man's name was given, but now when it comes to vengeance, the man is silent and only the king is mentioned. And having sent his armies, he destroyed those murderers, and burned their city. …

Commentary on Matthew ↗

Gregory the Dialogist

"But when the king learned of this, he sent his armies, destroyed those murderers, and burned their city." He destroys the murderers because he slays the persecutors. He burns their city with fire because not only their souls but also the flesh in which they had dwelt is tormented by the eternal flame of hell. It is said that he destroyed the murderers by sending armies because all judgment among humans is carried out through angels. For what are those hosts of angels if not the armies of our King? …

Forty Gospel Homilies, Homily 38 ↗

Thomas Aquinas

Then follows their punishment: but when the king had heard of it, he was angry, etc. Above he presented the spiritual penalty; here he presents the temporal one; hence above it was said a king, but here it says the king, because the name of man seems to pertain to mercy, but that of king to punishment; therefore here only king is said; Wisdom 14:17: those whom men could not honor in presence, because they dwelt far off, they made an evident image of the king whom they had a mind to honor, that by their earnestness they might worship …

Commentary on Matthew ↗