Disclaimer: Comments in this post are just a first glance at Luke 21.
So, this is not an exegetical explication by any stretch of the imagination. I’ve also tried to stay away from Daniel and the Apocalypse and some verses of Saint Paul. The next step will be to look at these altogether in a careful, legit manner. That’s not easy. You gotta start somewhere. Hold on for the ride:
[My comments]:
Luke 21:1 – As Jesus looked up, he saw the rich putting their gifts into the temple treasury. 2 He also saw a poor widow put in two very small copper coins. 3 “Truly I tell you,” he said, “this poor widow has put in more than all the others. 4 All these people gave their gifts out of their wealth; but she out of her poverty put in all she had to live on.” [Notice that Jesus didn’t stop her, saying that it was useless to support the Temple because it would soon be destroyed, what He will immediately speak about with His disciples:]
5 Some of his disciples were remarking about how the temple was adorned with beautiful stones and with gifts dedicated to God. But Jesus said, 6 “As for what you see here, the time will come when not one stone will be left on another; every one of them will be thrown down.” 7 “Teacher,” they asked, “when will these things happen? And what will be the sign that they are about to take place?” [With this Gospel, the question of the disciples is limited to what Jesus said about the Temple, not about the end of the world or any other time of persecution. Just a change of emphasis, not historical fact. Let’s see where Luke’s reporting of Jesus’ answer goes with this:]
8 He replied: “Watch out that you are not deceived. For many will come in my name, claiming, ‘I am he,’ and, ‘The time is near.’ Do not follow them. 9 When you hear of wars and uprisings, do not be frightened. These things must happen first, but the end will not come right away.” [Some of the disciples themselves would still be alive some 40 years later when all would be hearing of wars and uprisings as Titus neared Jerusalem to destroy the city and the Temple so completely that not one stone of that Temple would be left upon another. But Jesus now lifts His instruction from just the Temple to include “the end”, τέλος].
10 Then he said to them: “Nation will rise against nation, and kingdom against kingdom. 11 There will be great earthquakes, famines and pestilences in various places, and fearful events and great signs from heaven. [This reference to “great signs” is in the plural, meaning these signs are not The Great Sign or The Sign of the Son of Man, but rather, for instance, the many of the other signs in the heavens that we read about in the Apocalypse.]
12 “But before all this, they will seize you and persecute you. They will hand you over to synagogues and put you in prison, and you will be brought before kings and governors, and all on account of my name. 13 And so you will bear testimony to me. 14 But make up your mind not to worry beforehand how you will defend yourselves. 15 For I will give you words and wisdom that none of your adversaries will be able to resist or contradict. 16 You will be betrayed even by parents, brothers and sisters, relatives and friends, and they will put some of you to death. 17 Everyone will hate you because of me. 18 But not a hair of your head will perish. 19 Stand firm, and you will win life. [Πρὸ is a preposition which could refer to place, inescapable connected to a timeline, such as “but in the face of all this”, or “but at the same time, primarily”, but it seems simply to refer to successive events, which would make sense, moving from the pretense of legal process to all out murderous hacking one’s loved ones to death.]
20 “When you see Jerusalem being surrounded by armies, you will know that its desolation is near. [Does Jesus here return to the particular, merely the destruction of the building of the Temple? No Jew could do that. He uses “Jerusalem”, but the question is about the Temple. His description of the destruction of the Temple with Jerusalem some forty years on is exact. Yet, Jesus is speaking to the history of the Church in the future. Because of the Holy Sacrifice of the Lamb who Himself takes away the sins of the world, the Temple Sacrifice is now empty and void. One is to look to the Messiah, the Suffering Servant, and witness to Him. He Himself is the Temple as He Himself indicated. We are living stones in that Temple.] 21 Then let those who are in Judea flee to the mountains, let those in the city get out, and let those in the country not enter the city. [Again, all of Judea is mountainous. Thus, this refers to fleeing to the spiritual heights, to the spiritual Jerusalem, to be hidden, as Saint Paul says, with Christ, in God. Nothing material will help you in this flight, nothing from the Jerusalem of this world.]
22 For this is the time of punishment reckoning in fulfillment of all that has been written. [Maranatha! Come Lord Jesus!]
23 But woe to those in those days who are with-child pregnant women and those nursing! [I think of all the abortion, all the pharmaceutical deadly experimentation on babies, all the “vaccine” caused miscarriages, all the “vaccine” caused corruption of DNA passed on to any babies that survive, all the hatred of women and motherhood, with men dressing up as parodies of women, with women chopping themselves up…]
There will be great distress in the land and wrath against this people. 24 They will fall by the edge of the sword and will be taken as captives to all the nations. [While that’s an image of the death-marches that have happened right throughout history, this is specifically about the chosen people. “They” refers to “this people”, a reference to the Jews of Jerusalem, who, with their history in particular, are to choose to go with the earthy Jerusalem or the heavenly Jerusalem, but up to this point, generally speaking, have not chosen the heavenly Jerusalem in which we find their Messiah and ours. The Shoah, the Holocaust, was not some minor incident in the history of mankind. “Taken” makes me think of their trains…]
[But there will be a time of conversion:] Jerusalem will be trampled on by the Gentiles until the times of the Gentiles are fulfilled. [I can’t resist paraphrasing Saint Paul here: it is only when the Gentiles are converted that then the Jews would convert. The “Gentiles” reference is not to non-Jewish believers in Jesus, but rather to non-believers.]
[The following couple of verses seem to refer to an especially difficult time that are singled out for their extreme ferocity:] 25 “There will be signs in the sun, moon and stars. On the earth, nations will be in anguish and perplexity at the roaring and tossing of the sea. 26 People will faint from terror, apprehensive of what is coming on the world, for the heavenly bodies will be shaken.
27 At that time And then they will see the Son of Man coming in a cloud with power and great glory. 28 But with these things beginning to happen, stand erect and raise your heads, because your redemption is drawing near.” [This Second Coming of the Son of Man is successive to that time of particularly extreme ferocity. Jesus commands not to be fearful, not to hide, but rather, in all hope, to stand up straight and raise our heads.]
29 He told them this parable: “Look at the fig tree and all the trees. 30 When they sprout leaves, you can see for yourselves and know that summer is near. 31 Even so, when you see these things happening, you know that the kingdom of God is near. [Jesus commands us to read the signs of the times inasmuch as we can with the end that we are always ready: watch and pray.]
32 “Truly I tell you, this generation [of original sin] will certainly not pass away until all these things have happened. 33 Heaven and earth will pass away, but my words will never pass away.
34 “Be careful, or your hearts will be weighed down with carousing, drunkenness and the anxieties of life, and that day will close on you suddenly like a trap. [There is no one so blind as the one who darkens himself in sin. The sinner sets his own trap.] 35 For it will come on all those who live on the face of the whole earth. […even the rich who thinks he has power, even the government guy or politician who thinks he has power…] 36 Be always on the watch, and pray that you may be able to escape all that is about to happen, and that you may be able to stand before the Son of Man.” [And this gives us hope that we can stand before the Son of Man because He has set us there with Him.]
37 Each day Jesus was teaching at the temple[!], and each evening he went out to spend the night on the hill called the Mount of Olives [in plain view of the Temple], 38 and all the people came early in the morning to hear him at the temple[!].
One more comment: Luke has a very strong emphasis on the Temple, the living Temple being Jesus and us united with Him. He also narrows down the reason for the persecution, an attack on the family. The image of God in Genesis – male, female, marriage, family – is redeemed by the marriage of God with the Church by the wedding vows of Jesus (the consecrations at the Last Supper united with Calvary, my Body given for you in Sacrifice, my Blood poured out for you in Sacrifice). Look around, my friends, look around.
ARISE! LET US BE GOING! 
Re Luke 21:1-4
I wonder if the poor widow put Our Lord in mind of His Mother given His crucifixion was fast approaching. The poor widow putting her two very small copper coins into the temple treasury had nothing to gain and everything to lose in worldly terms, giving all she had out of love for God. Our Lord’s Mother, also a widow, was soon to give her all on Calvary out of love for God and for our sakes.
I love that.