The Olivet Discourse (found in Matthew 24, Mark 13, and Luke 21) is Jesus’ apocalyptic teaching to His disciples, and, as with all things pertaining to the end times, it typically draws out of us a strange mixture of curiosity, confusion, and perhaps some fear. Yet of all the questions that could be asked perhaps the most basic one is simply: what is Jesus talking about?
The two most common answers are either the destruction of Jerusalem and the temple in 70 AD or Christ’s Second Coming at the end of time. The difficulty of deciding between the two is that they both seem to be referenced. Matthew 24:2, Mark 13:2, and Luke 21:6, which declare that not one stone will remain on top of another, appear to directly predict the coming destruction of the temple by the Roman general, Titus, while Matthew 24:30, Mark 13:26, and Luke 21:27, which refer to the Son of Man coming in glory, each seem to pointedly envision the Second Coming of Christ.
My answer to whether the Olivet Discourse refers to 70 AD or the Second Coming is yes.
I believe that the overall purpose of the Olivet Discourse is to prepare Christ’s followers for the last days, of which the destruction of the temple and the Second Coming are bookend events. In other words, I believe that we are presently living through the end times, just as our fellow brothers and sisters have been doing for nearly two millennia now. Three texts blatantly support this interpretation:
Long ago, at many times and in many ways, God spoke to our fathers by the prophets, but in these last days he has spoken to us by his Son, whom he appointed the heir of all things, through whom also he created the world.Hebrews 1:1–2
Children, it is the last hour, and as you have heard that antichrist is coming, so now many antichrists have come. Therefore we know that it is the last hour.1 John 2:18
But Peter, standing with the eleven, lifted up his voice and addressed them: “Men of Judea and all who dwell in Jerusalem, let this be known to you, and give ear to my words. For these people are not drunk, as you suppose, since it is only the third hour of the day. But this is what was uttered through the prophet Joel:
“‘And in the last days it shall be, God declares,Acts 2:14–17
that I will pour out my Spirit on all flesh,
and your sons and your daughters shall prophesy,
and your young men shall see visions,
and your old men shall dream dreams;”
Notice that the author of Hebrews explicitly marks the last days as being when God has now spoken to His people by His Son rather than through the prophets alone. John points to the presence of many antichrists as a sign that we are in the last hour, and these are most probably the “false christs and false prophets” that Jesus warned of in the Olivet Discourse (Matthew 24:23, Mark 13:22).
Yet perhaps Peter’s sermon in Acts 2 is the most telling. After the Holy Spirit was first poured out upon the disciples, Peter proclaimed to the people gathered around them that Joel’s prophesy of the last days was being fulfilled in their midst, God’s Spirit was falling upon all His people no longer just the kings and prophets. Another element of interest is that the book of Joel is almost entirely focused upon the coming Day of the LORD, which is the final day of judgment that we now know is one and the same as the Second Coming of Christ (Revelation 19). Thus, the giving of the Holy Spirit at Pentecost signaled the beginning of the end of the world.
But what does this have to do with the destruction of the temple in 70 AD?
Although the last days began with the resurrection of Christ and the descent of the Holy Spirit at Pentecost, the Roman siege of Jerusalem was an apocalyptic event that has left a lasting mark upon the following 1950 years of history. Nick Needham notes that this event had a greater lasting impact upon the church than even the severe persecutions under emperors like Nero, Domitian, and Diocletian because it forcefully separated Christianity from Judaism. When the armies of Rome drew near, the Christians fled from Jerusalem as Christ commanded them to do (Matthew 24:16). Their refusal to defend the temple to the death was taken as a bitter betrayal by their fellow Jews. Thus, Christianity quickly became a predominately Gentile religion.
Since then Jesus’ words continue to apply. Both during that devastation and since, there have been false messiahs, wars and rumors of wars, natural disasters, and great tribulation upon God’s people. Yet for all these signs and sorrows, the day of Christ’s return will still come upon us like a thief in the night. Although many of the things that Jesus promised have already been fulfilled, life goes on as normal just as it did during the days of Noah before the flood. They did not realize that they were living in their last days until the flood swept them away; likewise, we are living in the last era of human history. When Christ returns, time as we know it will be wiped away, and every person will go to eternal life or eternal death. Like the great flood, His coming will be sudden and swift, and even if it is still a thousand years away, I do not think we will count it slowness but rather as an act of His glorious patience, giving us a little while longer to repent and return to Him (2 Peter 3:9).
 John seems to speak of an individual antichrist still to come, who is perhaps the man of lawlessness from 2 Thessalonians 2. Such discussions, however, must be saved for another post.