Destruction of the Temple Foretold
Mark 13:1-2 records a conversation between one of the disciples and Jesus as they left the temple. That disciple was very impressed by the beautiful buildings that formed the temple complex and the large stones that were used in building the temple. I'm sure it was an amazing sight, and was, of course, probably the most important public building to any of them.
The passage shows the reliance on things that look permanent in the eyes of the disciples. Knowing what was going to happen to Him shorty, I'm pretty sure Jesus was saddened in their focus on things and not people. That would be especially true since His death was to be the end of the Jewish need to sacrifice at all if they accepted Him as their Messiah.
Regardless, Jesus told them that not one stone would be left upon another. The destruction would be complete of all the great buildings they were looking at and admiring. This would be done by the Roman army in 70 A.D.
Timing and Signs of Second Coming
In this passage [Mark 13:3-14], there are two statements that make it clear that in these cases Christ is speaking of the final end times and not 70 A.D. Specifically, He speaks of the gospel being already spread to all nations. Second, He speaks of the abomination being set up in the temple which will occur at the middle of the 7 year period of Daniel's prophecy, and will initiate the Great Tribulation of the last 3 1/2 years.
In the scripture in Luke, Christ mentions the imminent surrounding of Jerusalem by the Romans as being the time to flee in 70 A.D. In this passage, He points out the desecration of the Temple by the Antichrist as being the time to flee. This helps to differentiate the two prophetical passages.
For today, there are words of wisdom to help us as well. Don't worry about what you will say in times of trouble. Let the Holy Spirit prompt you what to say. Are you afraid to witness? Let the Holy Spirit be your guide. Although the angelic messengers will be the final publishers of the gospel, worldwide, let us all do our parts in spreading the word of God and the way to be saved.
As further evidence this points to a perhaps near future, but future nonetheless, although there are certainly places in the world where there is extreme persecution of Christians and truly families turn against each other, know that it will be worse when the Anti-Christ is trying to stamp out Christianity. The challenge is still the same. Endure to the end and trust and have faith in God.
Many of the signs Jesus mentioned have come and gone many times over history. There has been war after war, earthquakes, famines, and troubles galore in the last 2,000 years. The Jews have suffered persecution, and so have the Christians. But these two groups have never been hated of all men for Jesus sake. After the rapture of the church, and the removal of all Christians from the face of the planet, followed by the tribulation period, however, any who take up the name of Christ at that point will truly be hated by everyone suffering God's judgment.
Families will turn against each other, even knowing that death will await those uncovered as Christian. Truly that level of hatred of Christians has yet to be seen, even though times have been tough for Christians in many nations and times. Worldwide hatred against the Christian religion hasn't been a thing.
The tribulation period will see war, famine, disease, and persecution at unprecedented levels. If you think of what the world will look like a few moments after the rapture happens, you can begin to see why. Hopefully at least 1/3 or more of the people on the earth will just disappear, no matter what they were doing.
Think of roads and freeways where 1/'3 of the cars go out of control at the same time. Think of some trains that will stop because the safety systems shut them down due to a missing crew, but another train keeps on going and plows into the back of the first because they were still there. Think of landing and departing planes and planes flying en route who may no longer have a pilot or air traffic control to sort things out.
1/3 or more of the people who plant and harvest crops may be gone (and it may be a higher percentage of farmers and ranchers because they may be closer to God). Think of 1/3 of all workers gone. How good are your emergency preparation plans? Will there be enough people to unload ships or move merchandise and food through hopelessly tangled roadways? All the death will be playground for disease.
Unscrupulous world leaders will seize the opportunity to expand their territory. War will be a real thing, probably world wide. Many of today's soldiers seem less likely to be devoutly religious.
Time to Flee to the Hills?
Mark 13:14-18 warns that when the Antichrist sets up shop in the temple, it is time for the Jews to flee to the hills. While this speaks of a future time, we should be encouraged to always be aware of our own surroundings as well. For Christians who live in perilous locations in the world, if the Holy Spirit tells you to flee, do it. Don't take time to gather up possessions. And if you have children who are to young to travel, sometimes persecution today can indeed lead to times of woe. Pray for good weather if you are going to have to flee. Don't give up faith in God.
Great Tribulation and Satan's Response
In Mark 13:19-25, Christ mentions God's divine mercy in shortening the time of tribulation so that there will be some people left at the end. But again, Christ mentions items that will be shared with John in the future as he writes Revelation. All is yet to come.
Pay particular attention to the warnings both here and above to false Christs trying to deceive people into believing in them instead of Jesus Himself. Many have come and gone in history, with generally small followings. But during the tribulation period there will be many more. And there will be many fewer Christians around to identify false Christs. Those who are Christian will be very new Christians (or perhaps some who had been in church for a long time but hadn't really accepted Christ).
The Second Coming
Mark 13:26-31 speaks of the second coming of Christ. The elect here are the Jewish people, not Christians, gathered back together to be an eternal nation. Just as the people who turn to Christ during the tribulation period need to be ready, so we need to be ready at any time to go in the rapture when Christ returns in the clouds. When He returns in the clouds here, it is to set up His earthly kingdom. Here, He isn't coming to take His church to heaven. He's coming to win.
The generation that this all begins to happen in won't pass away till the tribulation period is done and Christ returns to set up shop. He tells His listeners that even though the sun and inner planets will eventually change dramatically, and the earth will be burned to a cinder, His words will remain.
Exact Day and Hour of Second Coming not Known by Man
Christ then gives a parable in Mark 13:32-37 on being prepared. This parable is different than the others recorded in Matthew, but has the same theme - Watch and be ready!
He compares the coming of Christ would be like a man who took a long journey leaving his house under the control of the servants. He returned at a random time and warned that whenever he returned he should not find the servants slacking off.