Our Lord Jesus' Olivet discourse of Matthew 24, Mark 13, and Luke 21 confuses many. It contains a dual-fulfillment prophecy about the destruction of the buildings on the temple mount, both in 70 A.D., and then in final by Jesus when His feet touch down upon the Mount of Olives at His return. The hint He left for us to notice showing this is His prophecy that not one stone would be standing on top of another involving the temple mount buildings. Today, the Wailing Wall huge stones which were part of the foundation of the western wall of the temple complex, are witness that not one stone on top of another prophecy is yet to be fulfilled.
1. It's important to note that Jesus' disciples pointed out to Him the buildings on the Temple Mount, not the whole city of Jerusalem. The not one stone standing on top of another He didn't apply to the whole city; He applied that to the buildings on the temple mount which His disciples asked Him about. They were all destroyed by the Romans in 70 A.D., excepting the huge stones of the Western Wall. They still stand today and are often shown in news reels with orthodox Jews praying at it, a way that our Lord is letting us know the destruction of those stones that are atop another is still yet to come.
2. The Romans in 70 A.D. did not fulfill the "abomination of desolation" prophecy Jesus quoted from the Book of Daniel. Some try to stress that word 'desolation' as being about the destruction of Jerusalem by the Roman general Titus and his army in 70 A.D. However, that is not the proper application of that word 'desolation' per the Daniel prophecy in Daniel 11 where our Lord Jesus was pulling from. The "abomination of desolation" is about the spiritual desolation inside the temple at Jerusalem with the placing of an idol abomination in it for false worship. Historically, Antiochus Epiphanes in 170 B.C. did this, taking Jerusalem with an army, going inside the temple and sacrificing swine upon the altar thus spiritually desolating it, and then he placed an idol in Zeus worship and demanded all to bow to it. The Romans did no such working in 70 A.D., as the temple burned down before they could get control of it. Thus the "abomination of desolation" has to be for the very end of this present world, with the building of another Jewish temple in Jerusalem.
3. For several decades now, ultra-orthodox Jews in today's Jerusalem have been preparing the materials to build another Jewish temple in Jerusalem. They have setup the old Jewish Sanhedrin again. And they have been selected Levitical priests per blood lineage, and already have the cornerstone cut and ready to put in place. The orthodox Jews still believe they are under the old covenant worship. That old covenant worship requires a temple style worship with sacrifices. That has been part of their plan since trying to become a nation state again since the Romans destroyed Jerusalem in 70 A.D.
4. Jesus gave the main signs of the end in His Olivet discourse. They are the signs of the Seals in Revelation 6 which He gave to His Church.