20. And when you shall see Jerusalem compassed with armies, then know that the desolation thereof is nigh.
21. Then let them which are in Judea flee to the mountains; and let them which are in the midst of it depart out; and let not them that are in the countries enter thereinto.
22. For these be the days of vengeance, that all things which are written may be fulfilled.
23. But woe to them that are with child, and to them that give suck, in those days! for there shall be great distress in the land, and wrath upon this people.
24. And they shall fall by the edge of the sword, and shall be led away captive into all nations: and Jerusalem shall be trodden down of the Gentiles, until the times of the Gentiles be fulfilled.
BEDE, Hitherto our Lord had been speaking of those things which were to come to pass for forty years, the end not yet coming. He now describes the very end itself of the desolation, which was accomplished by the Roman army; as it is said, And when you shall see Jerusalem compassed, &c.
EUSEB. By the desolation of Jerusalem, He means that it was never again to be set up, or its legal rites to be reestablished, so that no one should expect, after the coming siege and desolation, any restoration to take place, as there was in the time of the Persian king, Antiochus the Great, and Pompey.
AUG. These words of our Lord, Luke has here related to show, that the abomination of desolation which was prophesied by Daniel, and of which Matthew and Mark had spoken, was fulfilled at the siege of Jerusalem.
AMBROSE; 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.
EUSEB. Now our Lord, foreseeing that there would be a famine in the city, warned His disciples in the siege that was coming, not to betake themselves to the city as a place of refuge, and under God's protection, but rather to depart from thence, and flee to the mountains.
BEDE; The ecclesiastical history relates, that all the Christians who were in Judea, when the destruction of Jerusalem was approaching, being warned of the Lord, departed from that place, and dwelt beyond the Jordan in a city called Pella, until the desolation of Judea was ended.
AUG And before this, Matthew and Mark said, And let him that is on the housetop not come down into his house; and Mark added, neither enter therein to take any thing out of his house; in place of which Luke subjoins, And let them which are in the midst of it depart out.
BEDE; But how, while the city was already compassed with an army, were they to depart out? except that the preceding word "then" is to be referred, not to the actual time of the siege, but the period just before, when first the armed soldiers began to disperse themselves through the parts of Galilee and Samaria.
AUG. But where Matthew and Mark have written, Neither let him which is in the field return back to take his clothes, Luke adds more clearly, And let not them that are in the countries enter thereinto, for these be the days of vengeance, that all the things which are written may be fulfilled.
BEDE; And these are the days of vengeance, that is, the days exacting vengeance for our Lord's blood.
AUG. Then Luke follows in words similar to those of the other two; But woe to them that are with child, and them that give suck in those days; and thus has made plain what might otherwise have been doubtful, namely, that what was said of the abomination of desolation belonged not to the end of the world, but the taking of Jerusalem.
BEDE; He says then, Woe to them that nurse, or give suck, as some interpret it, whose womb or arms now heavy with the burden of children, cause no slight obstacle to the speed of flight.
THEOPHYL. But some say that the Lord hereby signified the devouring of children, which Josephus also relates.
CHRYS. He next assigns the cause of what he had just now said, For there shall be great distress in the land, and wrath upon this people. For the miseries that took hold of them were such as, in the words of Josephus, no calamity can henceforth compare to them.
EUSEB. For so in truth it was, that when the Romans came and were taking the city, many multitudes of the Jewish people perished in the mouth of the sword; as it follows, And they shall fall by the edge of the sword. But still more were cut off by famine. And these things happened at first indeed under Titus and Vespasian, but after them in the time of Hadrian the Roman general, when the land of their birth was forbidden to the Jews Hence it follows, And they shall be led away captive into all nations. For the Jews filled the whole land, reaching even to the ends of the earth, and when their land was inhabited by strangers, they alone could not enter it; as it follows, And Jerusalem shall be trodden down of the Gentiles, until the times of the Gentiles be fulfilled.
BEDE; Which indeed the Apostle makes mention of when he says, Blindness in part is happened to Israel, and so all Israel shall be saved. Which when it shall have gained the promised salvation, hopes not rashly to return to the land of its fathers.
AMBROSE; 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. But according to the spiritual meaning, he is well brought in, because he desires to impress firmly on the affections the footstep of his unbelief, disputing from the Scriptures that he is Christ. Then shall come desolation, for very many falling away shall depart from the true religion. Then shall be the day of the Lord, since as His first coming was to redeem sin, so also His second shall be to subdue iniquity, lest more should be carried away by the error of unbelief. There is also another Antichrist, that is, the Devil, who is trying to besiege Jerusalem, i.e. the peaceful soul, with the hosts of his law. When then the Devil is in the midst of the temple, there is the desolation of abomination. But when upon any one in trouble the spiritual presence of Christ has shone, the unjust one is cast out, and righteousness begins her reign. There is also a third Antichrist, as Arius and Sabellius and all who with evil purpose lead us astray. But these are they who are with child, to whom woe is denounced, who enlarge the size of their flesh, and the step of whose inmost soul waxes slow, as those who are worn out in virtue, pregnant with vice. But neither do those with child escape condemnation, who though firm in the resolution of good acts, have not yet yielded any fruits of the work undertaken. These are those which conceive from fear of God, but do not all bring forth. For there are some which thrust forth the word abortive before their delivery. There are others too which have Christ in the womb, but have not yet formed Him. Therefore she who brings forth righteousness, brings forth Christ. Let us also hasten to nourish our children, lest the day of judgment or death find us as it were the parents of an imperfect offspring. And this you will do if you keep all the words of righteousness in your heart, and wait not the time of old age, but in your earliest years, without corruption of your body, quickly conceive wisdom, quickly nourish it. But at the end shall all Judea be made subject to the nations which shall believe, by the mouth of the spiritual sword, which is the two-edged word.
25. And there shall be signs in the sun, and in the moon, and in the stars; and upon the earth distress of nations, with perplexity; the sea and the waves roaring;
26. Men's hearts failing them for fear, and for looking after those things which are coming on the earth: for the powers of heaven shall be shaken.
27. And then shall they see the Son of man coming in a cloud with power and great glory.
BEDE; The events which were to follow the fulfillment of the times of the Gentiles He explains in regular order, saying, There shall be signs in the sun, and in the moon, and in the stars.
AMBROSE; All which signs are more clearly described in Matthew, Then shall the sun be darkened, and the moon shall not give her light, and the stars shall fall from heaven.
EUSEB. For at that time when the end of this perishing life shall be accomplished, and, as the Apostle says, The fashion of this world passes away, then shall succeed a new world in which instead of sensible light, Christ Himself shall shine as a sunbeam, and as the King of the new world, and so mighty and glorious will be His light, that the sun which now dazzles so brightly, and the moon and all the stars, shall be hidden by the coming of a far greater light.
CHRYS For as in this world the moon and the stars are soon dimmed by the rising of the sun, so at the glorious appearance of Christ shall the sun become dark, and the moon not shed her ray, and the stars shall fall from heaven, stripped of their former attire, that they may put on the robe of a better light.
EUSEB. What things shall befall the world after the darkening of the orbs of light, and whence shall arise the straitening of nations, He next explains as follows, And of the earth distress of nations, by reason of the confusion of the roaring of the sea. Wherein He seems to teach, that the beginning of the universal change will be owing to the failing of the watery substance. For this being first absorbed or congealed, so that no longer is heard the roaring of the sea, nor do the waves reach the shore because of the exceeding drought, the other parts of the world, ceasing to obtain the usual vapor which came forth from the watery matter, shall undergo a revolution. Accordingly since the appearance of Christ must put down the prodigies which resist God, namely, those of Antichrist, the beginnings of wrath shall take their rise from droughts, such as that neither storm nor roaring of the sea be any more heard.
And this event shall be succeeded by the distress of the men who survive; as it follows, Men's hearts being dried up for fear, and looking after those things which shall come upon the whole world. But the things that shall then come upon the world He proceeds to declare, adding, For the powers of heaven shall be shaken.
THEOPHYL. Or else, When the higher world shall be changed, then also the lower elements shall suffer loss; whence it follows, And on the earth distress of nations, &c. As if He said, the sea shall roar terribly, and its shores shall be shaken with the tempest, so that of the people and nations of the earth there shall be distress, that is, a universal misery, so that they shall pine away from fear and expectation of the evils which are coming upon the world.
AUG. But you will say, your punishment compels you to confess that the end is now approaching, seeing the fulfillment of that which was foretold. For it is certain there is no country, no place in our time, which is not affected or troubled. But if those evils which mankind now suffer are sure signs that our Lord is now about to come, what means that which the Apostle says, For when they shall say peace and safety. Let us see then if it be not perhaps better to understand the words of prophecy to be not so fulfilled, but rather that they will come to pass when the tribulation of the whole world shall be such that it shall belong to the Church, which shall be troubled by the whole world, not to those who shall trouble it. For they are those who shall say, Peace and safety. But now these evils which are counted the greatest and most immoderate, we see to be common to both the kingdoms of Christ and the Devil. For the good and the evil are alike afflicted with them, and among these great evils is the yet universal resort to licentious feasts. Is not this the being dried up from fear, or rather the being burnt up from lust?
THEOPHYL. But not only shall men be tossed about when the world shall be changed, but angels even shall stand amazed at the terrible revolutions of the universe. Hence it follows, And the powers of heaven shall be shaken.
GREG. For whom does He call the powers of heaven, but the angels, dominions, principalities, and powers? which at the coming of the strict Judge shall then appear visibly to our eyes, that they may strictly exact judgment of us, seeing that now our invisible Creator patiently bears with us.
EUSEB. When also the Son of God shall come in glory, and shall crush the proud empire of the son of sin, the angels of heaven attending Him, the doors of heaven which have been shut from the foundation of the world shall be opened, that the things that are on high may be witnessed.
CHRYS. Or the heavenly powers shall be shaken, although themselves know it not. For when they see the innumerable multitudes condemned, they shall not stand there without trembling.
BEDE; Thus it is said in Job, the pillars of heaven tremble and are afraid at his reproof. What then do the boards do, when the pillars tremble? what does the shrub of the desert suffer, when the cedar of Paradise is shaken?
EUSEB. Or the powers of heaven are those which preside over the sensible parts of the universe, which indeed shall then be shaken that they may attain to a better state. For they shall be discharged from the ministry with which they serve God toward the sensible bodies in their perishing condition.
AUG. But that the Lord may not seem to have foretold as extraordinary those things concerning His second coming, which were wont to happen to this world even before His first coming, and that we may not be laughed at by those who have read more and greater events than these in the history of nations, I think what has been said may be better understood to apply to the Church. For the Church is the sun, the moon, and the stars, to whom it was said, Fair as the moon, elect as the sun. And she will then not be seen for the unbounded rage of the persecutors.
AMBROSE; While many also fall away from religion, clear faith will be obscured by the cloud of unbelief, for to me that Sun of righteousness is either diminished or increased according to my faith; and as the moon in its monthly wanings, or when it is opposite the sun by the interposition of the earth, suffers eclipse, so also the holy Church when the sins of the flesh oppose the heavenly light, cannot borrow the brightness of divine light from Christ's rays. For in persecutions, the love of this world generally shuts out the light of the divine Sun; the stars also fall, that is, men who shine in glory fall when the bitterness of persecution waxes sharp and prevails. And this must be until the multitude of the Church be gathered in, for thus are the good tried and the weak made manifest.
AUG. But in the words, And upon the earth distress of nations, He would understand by nations, not those which shall be blessed in the seed of Abraham, but those which shall stand on the left hand.
AMBROSE; So severe then will be the manifold fires of our souls, that with consciences depraved through the multitude of crimes, by reason of our fear of the coming judgment, the dew of the sacred fountain will be dried upon us. But as the Lord's coming is looked for, in order that His presence may dwell in the whole circle of mankind or the world, which now dwells in each individual who has embraced Christ with his whole heart, so the powers of heaven shall at our Lord's coming obtain an increase of grace, and shall be moved by the fullness of the Divine nature more closely infusing itself. There are also heavenly powers which proclaim the glory of God, which shall be stirred by a fuller infusion of Christ, that they may see Christ.
AUG. Or the powers of heaven shall be stirred, because when the ungodly persecute, some of the most stout-hearted believers shall be troubled.
THEOPHYL. It follows, And then shall they see the Son of man coming in the clouds. Both the believers and unbelievers shall see Him, for He Himself as well as His cross shall glisten brighter than the sun, and so shall be observed of all.
AUG. But the words, coming in the clouds, may be taken in two ways. Either coming in His Church as it were in a cloud, as He now ceases not to come. But then it shall be with great power and majesty, for far greater will His power and might appear to His saints, to whom He will give great virtue, that they may not be overcome in such a fearful persecution. Or in His body in which He sits at His Father's right hand He must rightly be supposed to come, and not only in His body, but also in a cloud, for He will come even as He went away, And a cloud received him out of their sight.
CHRYS. For God ever appears in a cloud, according to the Psalms, clouds and darkness are round about him. Therefore shall the Son of man come in the clouds as God, and the Lord, not secretly, but in glory worthy of God. Therefore He adds, with great power and majesty.
CYRIL; Great must be understood in like manner. For His first appearance He made in our weakness and lowliness, the second He shall celebrate in all His own power.
GREG. For in power and majesty will men see Him, whom in lowly stations they refused to hear, that so much the more acutely they may feel His power, as they are now the less willing to bow the necks of their hearts to His sufferings.
28. And when these things begin to come to pass, then look up, and lift up your heads; for your redemption draws nigh.
GREG. Having in what has gone before spoken against the reprobate, He now turns His words to the consolation of the elect; for it is added, When these things begin to be, look up, and lift up your heads, for your redemption draws nigh; as if he says, When the buffetings of the world multiply, lift up your heads, that is, rejoice your hearts, for when the world closes whose friends you are not, the redemption is near which you seek. For in holy Scripture the head is often put for the mind, for as the members are ruled by the head, so are the thoughts regulated by the mind. To lift up our heads then, is to raise up our minds to the joys of the heavenly country.
EUSEB. Or else, To those that have passed through the body and bodily things, shall be present spiritual and heavenly bodies: that is, they will have no more to pass the kingdom of the world, and then to those that are worthy shall be given the promises of salvation. For having received the promises of God which we look for, we who before were crooked shall be made upright, and we shall lift up our heads who were before bent low; because the redemption which we hoped for is at hand; that namely for which the whole creation waits.
THEOPHYL. That is, perfect liberty of body and soul. For as the first coming of our Lord was for the restoration of our souls, so will the second be manifested to the restoration of our bodies.
EUSEB. He speaks these things to His disciples, not as to those who would continue in this life to the end of the world, but as if uniting in one body of believers in Christ both themselves and us and our posterity, even to the end of the world.
Catena Aurea Luke 21
The Martyrology gives these details: "At Rome on the Via Salaria the death of the holy martyr, the aged Saturninus, and of the deacon Sisinius. Under the emperor Maximianus they suffered long in prison. The prefect of Rome ordered them placed on the rack till their joints were torn loose, then beaten with knotted whips, and burnt with torches; at last removed from the rack, they were beheaded." According to the inscription on his tomb by Pope St. Damasus, Saturninus hailed from Carthage. The Acts of Marcellus say he was condemned as a frail old man to carry sand for the construction of the Baths of Diocletian; but when by his patience and prayer and encouragement he led many to the faith, he was beheaded. 
