v. 20-24 Jesus said, "When you see Jerusalem being surrounded by armies, you will know that its desolation is near. 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. For this is the time of punishment in fulfillment of all that has been written. How dreadful it will be in those days for pregnant women and nursing mothers! There will be great distress in the land and wrath against this people. They will fall by the sword and will be taken as prisoners to all the nations. Jerusalem will be trampled on by the Gentiles until the times of the Gentiles are fulfilled."
"The times of the Gentiles began with Babylon's destruction of Jerusalem in 586 B.C. and the exile of the Jewish people. Israel was no longer an independent nation but was under the control of Gentile rulers." NIV notes
During the time Jesus was alive Israel was controlled by the Roman empire. In 70 A.D. a Roman general destroyed the city, which is what Jesus was talking about in these scriptures. Jesus was also saying that the domination of God's people by His enemies will continue until He says it will end.
v. 25-28 Jesus said, "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. Men will faint from terror, apprehensive of what is coming on the world, for the heavenly bodies will be shaken. At that time they will see the Son of Man coming in a cloud with power and great glory. When these things begin to take place, stand up and life up your heads, because your redemption is drawing near."
This picture of the future is gloomy and can cause fear. We are not to fear because now until the end has been written already and God is in control. We think that the natural disasters are bad now, I think that we have no clue to the massive forces that are going to be at work when this is happening. I can not even imagine what it would be like to see Jesus coming back in a cloud! When you believe, you have faith that you will be taken care of because you are on the winning side. Jesus does not tell us to cower in fear when we see these things. We are supposed to stand up and lift our heads to focus on God.
v. 29-33 Jesus said, "Look at the fig tree and all the trees. When they sprout leaves, you can see for yourselves and know that summer is near. Even so, when you see these things happening, you know that the kingdom of God is near. I tell you the truth, this generation will certainly not pass away until all these things have happened. Heaven and earth will pass away, but my words will never pass away." There will be great signs that will let us know that the time has come for Jesus to come back to earth. I think that when Jesus says that this generation will not pass away I think He means all of us because these events have not come to pass completely.
v. 34-38 Jesus tells of remaining watchful. "Be careful, or your hearts will be weighted down with dissipation, drunkenness and the anxieties of life, and that day will close on you unexpectedly like a trap. For it will come upon all those who live on the face of the whole earth. 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." Every day Jesus would teach in the temple then go out to spend the night on the hill called the Mount of Olives. The people came early every day to hear him speak.
We are to be on guard always. We do not know when the end will come and that means we are to be ready at any moment. Do not let your mind be distracted with the issues of this world. There are so many that worry about things that take their focus off of Him. Everyone that is living during this time will be going through the same things. If there is a massive flood I think that Christian's houses will be destroyed just like non-believers houses. I believe this means that at this point not even Christians will be immune from the violent changes to the environment and the earth. Although we are supposed to pray that we may be able to escape and stand before Jesus. The few days between when He road into town on a donkey and his death He kept teaching. We should do the right thing no matter what our circumstances. Every night Jesus went away from the busy town to a quiet hill. Sometimes getting away from a situation will give you rest and strength.