Theophylact of Ohrid

Now the Lord speaks most clearly about the captivity of Jerusalem. Therefore I think that the words "but before all these" (Lk. 21:12) should be understood thus: before the famine and pestilence, and the other calamities that will occur at the time of the end of the world, you, the apostles, will be driven out, and so forth. Then for Jerusalem too calamities will come. Since they thought that the buildings of the temple would be destroyed at the time of the end, the Lord says: no! …

Commentary on Luke ↗

Augustine of Hippo

Anyone can see that he refers to that city when Christ says, "When you shall see Jerusalem surrounded by an army, then know that its desolation is near." Anyone can see that these words refer to the last coming of the Lord when he says, "When you shall see these things come to pass, know that the kingdom of God is near." When he says, "Alas for those who are with child and for those who give suck in those days! Pray that your flight may not be in winter or on a sabbath. …

Letter 199 ↗

Ambrose of Milan

For the Jews thought that the abomination of desolation took place when the Romans, in mockery of a Jewish observance, cast a pig's head into the temple. Now mystically, the abomination of desolation is the coming of Antichrist, for with ill-omened sacrilege he pollutes the innermost recesses of the heart, sitting as it is literally in the temple, that he may claim to himself the throne of divine power. …

Catena Aurea by Aquinas ↗

Bede

But when you shall see Jerusalem surrounded by an army, then know that her desolation is near. Thus far these things which were to be for forty years, with the end not yet coming; here the very end of the desolation, which was made by the Roman army, is explained by the Lord's words.

On the Gospel of Luke ↗