Click here to veiw the Matt 24 Mark 12-13 and Luke 21 side by side chart

First the Abomination Standing in the Holy Place. Then the Jews were taken captive into the nations . Until the time of the Gentile be fulfilled 

Now the events called the "sorrows " (birth pangs) begin. These are the tribulation of those days that happen before the return of Christ.

The End Days of Our Time

At this point the first question "Teacher, when therefore will these things happen?"asked by the disciples, concerning the destruction of the Temple, has been answered......but Jesus, knowing that the second question, and what {will be} the sign of Your coming, and of the end of the age?"  would be a later time. The disciples believed and taught that this destruction would bring on the end of the age.

The days of sorrow that Jesus began the discourse with, will begin the end of days for us. They are the birth pangs of the end of the age. 

Jesus repeats what He said at the beginning of the Discourse and then says behold I have already told you this.

Mat 24:23 "Then if anyone says to you, 'Behold, here is the Christ,' or 'There {He is,}' do not believe {him.} (:24) "For false Christs and false prophets will arise and will show great signs and wonders, so as to mislead, if possible, even the elect.
Mat 24:25 "Behold, I have told you in advance.

Mar 13:21 "And then if anyone says to you, 'Behold, here is the Christ'; or, 'Behold, {He is} there'; do not believe {him;} (:22) for false Christs and false prophets will arise, and will show signs and wonders, in order to lead astray, if possible, the elect.
Mar 13:23 "But take heed; behold, I have told you everything in advance.

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"behold, I have told you beforehand".  In Greek it is idouproereo humin

idou (look or see), proereo (I have said this previously) humin ([to] you.)

proereo {pro-er-eh'-o}

1) to say before a) to say in what precedes, to say above
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In other words, I have told you about this part already. He told of the false Christ and everything else that has to do with the beginning of sorrows when He first began the discourse. Remember, Luke said "But before these things", meaning these other things will come first and then the 'beginning of sorrows' (birth pangs) will take place................... before the end of the age and My return.

So let's look at what Mark wrote about the days of the beginning of sorrows, the birth pangs ushering in the end of this age.

Mar 13:5 And Jesus answering them began to say, Take heed lest any [man] deceive you: (:6) For many shall come in my name, saying, I am [Christ]; and shall deceive many. (:7) And when ye shall hear of wars and rumours of wars, be ye not troubled: for [such things] must needs be; but the end [shall] not [be] yet.

(:8) For nation shall rise against nation, and kingdom against kingdom: and there shall be earthquakes in divers places, and there shall be famines and troubles: these [are] the beginnings of sorrows.
 
 

The beginning of sorrows are the calamities that take place before the Messiah returns. They are the signs of the times we are to look for to know the time is near. These are actually the same as the seals in the book of Revelation.

He goes on to say that we are not to look in the desert or the upper room for Him, but to the sky where we will see Him returning on the clouds to gather the elect (believers).

Mat 24:27 "For just as the lightning comes from the east and flashes even to the west, so will the coming of the Son of Man be.
(:28) "Wherever the corpse is, there the vultures will gather."

Note: In another part of Luke he says the apostles asked "where Lord? " Meaning where should we gather so the angels can find us.  Jesus answers  “Wherever the corpse is, there the vultures will gather.”  In other words the angels will find you where ever you are.   The eagle/vulture is symbolic of the angels that will do the gathering. This is the day of the resurrection of the dead and the rapture (catching up) of the living IN CHRIST.
 

Mat 24:29 "But immediately after the tribulation of those days THE SUN WILL BE DARKENED, AND THE MOON WILL NOT GIVE ITS LIGHT, AND THE STARS WILL FALL from the sky, and the powers of the heavens will be shaken.
Mar 13:24 "But in those days, after that tribulation, THE SUN WILL BE DARKENED AND THE MOON WILL NOT GIVE ITS LIGHT, (:25) AND THE STARS WILL BE FALLING from heaven, and the powers that are in the heavens will be shaken.
Luk 21:25 "There will be SIGNS IN THE MOON AND THE STARS, and on the earth dismay among nations, in perplexity at the roaring of the sea and the waves, (:26) men fainting from fear and the expectation of the things which are coming upon the world; for the powers of the heavens will be shaken.

(Note: Also see Revelation 8, the 6th seal, for this same event)

Immediately after the tribulation of Matt 24: 7 For nation shall rise against nation, and kingdom against kingdom: and there shall be famines, and pestilences, and earthquakes, in divers places. (This is a war in the Middle East, also seen in the 4th and 5th seals of Revelation.  1/4 of nations of the world will be involved in it. and the rider Death will use war, famine and disease, which war causes, and the beasts of the earth to kill.)   The signs that follow are caused by a nuclear weapon going off in the middle east, which is the 6th seal event.  The sun and moon are darkened by the thick derbies in the air. The sun is like sackcloth and yet the moon is only red, which means by nightfall there is less debris. The mountains shake out of there place like an earthquake. The stars appear to be falling from the sky, but I think these are actually bombs of war.

Mat 24:30 "And then the sign of the Son of Man will appear in the sky, and then all the tribes of the earth will mourn, and they will see the SON OF MAN COMING ON THE CLOUDS OF THE SKY with power and great glory.
Mar 13:26 "Then they will see THE SON OF MAN COMING IN CLOUDS with great power and glory.
Luk 21:27 "Then they will see THE SON OF MAN COMING IN A CLOUD with power and great glory.

Mat 24:31 "And He will send forth His angels with A GREAT TRUMPET and THEY WILL GATHER TOGETHER His elect from the four winds, from one end of the sky to the other.
Mar 13:27 "And then He will send forth the angels, and will gather together His elect from the four winds, from the farthest end of the earth to the farthest end of heaven.
Luk 21:28 "But when these things begin to take place, straighten up and lift up your heads, because your redemption is drawing near."

Luke had talked of the time of the end and Jesus' return once before.

Luk 17:22 And He said to the disciples, "The days will come when you will long to see one of the days of the Son of Man, and you will not see it. (:23) "They will say to you, 'Look there! Look here!' Do not go away, and do not run after {them.}
Luk 17:24 "For just like the lightning, when it flashes out of one part of the sky, shines to the other part of the sky, so will the Son of Man be in His day.
Luk 17:25 "But first He must suffer many things and be rejected by this generation.
Luk 17:26 "And just as it happened in the days of Noah, so it will be also in the days of the Son of Man:
Luk 17:27 they were eating, they were drinking, they were marrying, they were being given in marriage, until the day that Noah entered the ark, and the flood came and destroyed them all.
Luk 17:28 "It was the same as happened in the days of Lot: they were eating, they were drinking, they were buying, they were selling, they were planting, they were building;
Luk 17:29 but on the day that Lot went out from Sodom it rained fire and brimstone from heaven and destroyed them all.

Luk 17:30 "It will be just the same on the day that the Son of Man is revealed.
Luk 17:31 "On that day, the one who is on the housetop and whose goods are in the house must not go down to take them out; and likewise the one who is in the field must not turn back.
Luk 17:32 "Remember Lot's wife.
Luk 17:33 "Whoever seeks to keep his life will lose it, and whoever loses {his life} will preserve it.
Luk 17:34 "I tell you, on that night there will be two in one bed; one will be taken and the other will be left.
Luk 17:35 "There will be two women grinding at the same place; one will be taken and the other will be left.
Luk 17:36 ["Two men will be in the field; one will be taken and the other will be left."]

Luk 17:37 And answering they *said to Him, "Where, Lord?" And He said to them, "Where the body {is,} there also the vultures will be gathered."

This is speaking of the resurrection of the dead and the rapture of the living.