Also, in the Olivet discourse it has been traditionally interpreted to involve two different points in time... "the beginning of the end" and then, the "tribulation" (I wish I had a reference for you, but I don't. I will have to do some snooping around...).
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For some context... Matthew c. xxiv verse i-v
1 And Jesus being come out of the temple, went away. And his disciples came to shew him the buildings of the temple.
2 And he answering, said to them: Do you see all these things? Amen I say to you, there shall not be left here a stone upon a stone that shall not be destroyed.
3 And when he was sitting on mount Olivet, the disciples came to him privately, saying: Tell us when shall these things be? And what shall be the sign of thy coming and of the consummation of the world?
4 And Jesus answering, said to them: Take heed that no man seduce you.
5 For many will come in my name saying, I am Christ. And they will seduce many.
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Exhibit a: Matthew ch. xxiv verse vi-xiv
6 And you shall hear of wars and rumours of wars. See that ye be not troubled. For these things must come to pass: but the end is not yet.
7 For nation shall rise against nation, and kingdom against kingdom: And there shall be pestilences and famines and earthquakes in places.
8 Now all these are the beginnings of sorrows.
9 Then shall they deliver you up to be afflicted and shall put you to death: and you shall be hated by all nations for my name's sake.
10 And then shall many be scandalized and shall betray one another and shall hate one another.
11 And many false prophets shall rise and shall seduce many.
12 And because iniquity hath abounded, the charity of many shall grow cold.
13 But he that shall persevere to the end, he shall be saved.
14 And this gospel of the kingdom shall be preached in the whole world, for a testimony to all nations: and then shall the consummation come.
"...but the end is not yet.";"Now all these are the beginnings of sorrows", the beginning of the end, not the end. Many people confuse the two. "...and then the consummation shall come.", meaning only after this event shall the tribulation begin to happen.
Matthew ch. xxiv verse xv-xxi
15 When therefore you shall see the abomination of desolation, which was spoken of by Daniel the prophet, standing in the holy place: he that readeth let him understand.
16 Then they that are in Judea, let them flee to the mountains:
17 And he that is on the housetop, let him not come down to take any thing out of his house:
18 And he that is in the field, let him not go back to take his coat.
19 And woe to them that are with child and that give suck in those days.
20 But pray that your flight be not in the winter or on the sabbath.
21 For there shall be then great tribulation, such as hath not been from the beginning of the world until now, neither shall be.
"For there shall be then great tribulation...", here now indicating the tribulation will have begun after this point in time.
So, the abomination of desolation is the "trigger point" of the great tribulation. Which is when the Antichrist declares himself to be the Most High.