If you had actually read my post you would have seen that what I said was Matthew 24 is about two things: the destruction of Jerusalem and the second coming of Christ (a future event to us today). Jesus used the destruction of Jerusalem as a type of His eventual second coming, which has yet to take place. 1st century Jews saw history as cyclicle. The 1st century Jewish Christian would have read Matthew 24 and looked at the events of 70 AD and seen that the event of their time pictured the eventual personal return of Christ.
Now, you say all things written in the OT prophecy were fullfilled in 70 AD. What about Isaiah 65:17-25? Those texts refer to a new heaven and new earth which the Lord will create. It says He will create Jerusalem rejoicing and there will be no more weeping or crying. The wolf and the lamb shall feed together. Has that ultimately been fullfilled? How about Psalm 102:25-26? "Of old hast thou laid the foundation of the earth: and the heavens are the work of thy hands. They shall perish, but thou shalt endure: yea, all of them shall wax old like a garment; as a vesture shalt thou change them, and they shall be changed." Hebrews says this is talking about the world to come. Has that been ultimately fullfilled yet?
Now you point to a text in Luke 21. Look at Luke 24:44 where the risen Lord tells the eleven that He had previously told them that all things written concerning Him in the law, the prophets, and the psalms must be fullfilled. Then He tells them to go forth and preach the gospel abroad, which is a fullfillment of prophecy, Isaiah 49 for example. Then He tells them to tarry in Jerusalem until they be endued with power from on high, meaning the Holy Spirit. This was done on the day of Pentecost in Acts 2 and Peter quotes a prophecy from Joel 2 as being fullfilled that day. The point I am making is this: Jesus told them that "all things" written concerning Him are fullfilled, but then gives them instructions which will fullfill other things written concerning Him, the gospel, and the church. Obviously, by all things He didn't mean every single prophecy and text in the OT had been fullfilled, but rather that all concerning His sufferings.
Now, you say all things written in the OT prophecy were fullfilled in 70 AD. What about Isaiah 65:17-25? Those texts refer to a new heaven and new earth which the Lord will create. It says He will create Jerusalem rejoicing and there will be no more weeping or crying. The wolf and the lamb shall feed together. Has that ultimately been fullfilled? How about Psalm 102:25-26? "Of old hast thou laid the foundation of the earth: and the heavens are the work of thy hands. They shall perish, but thou shalt endure: yea, all of them shall wax old like a garment; as a vesture shalt thou change them, and they shall be changed." Hebrews says this is talking about the world to come. Has that been ultimately fullfilled yet?
Now you point to a text in Luke 21. Look at Luke 24:44 where the risen Lord tells the eleven that He had previously told them that all things written concerning Him in the law, the prophets, and the psalms must be fullfilled. Then He tells them to go forth and preach the gospel abroad, which is a fullfillment of prophecy, Isaiah 49 for example. Then He tells them to tarry in Jerusalem until they be endued with power from on high, meaning the Holy Spirit. This was done on the day of Pentecost in Acts 2 and Peter quotes a prophecy from Joel 2 as being fullfilled that day. The point I am making is this: Jesus told them that "all things" written concerning Him are fullfilled, but then gives them instructions which will fullfill other things written concerning Him, the gospel, and the church. Obviously, by all things He didn't mean every single prophecy and text in the OT had been fullfilled, but rather that all concerning His sufferings.