If I could preface all of this with one command, it would be, "Read Matthew Chapter 24 in its entirety before reading any farther.
... ... ...
Now, did you read it? Good. Now, for years, Christians have claimed that Biblical prophecy buttresses our belief in the reliability of the scriptures. Many unbelievers, however, point to Matthew chapter 24 as an example of unfulfilled prophecy.
In the passage, Jesus predicts a number of things which, according to some Christians, have never happened.
These predictions include:
a) False messiahs (v. 4-5)
b) Wars and rumors of war (v. 6-7)
c) Famines and Earthquakes (v. 7)
d) Times of unmatched persecution (v. 9-14)
e) Lawlessness (v. 12)
f) Gospel preached to the whole world (v. 14)
g) The Abomination of Desolation (Predicted in Daniel 9:24-27; Reiterated in v. 15)
h) The Great Tribulation (v. 21-22)
i) Jesus comes with judgement, on the clouds (v. 29-30)
Now, the short version of it is that in verse 34, Jesus says something very important regarding the timetable for the things he is predicting. "I tell you the truth, this generation will certainly not pass away until all these things have happened." This really is the clenching idea; did Jesus' predictions come true within the lifetime of those listening to His words, or not? (The Geneva Institute for Reformed Studies has done a nice little study demonstrating how each of these predictions of Jesus have, historically speaking, been fulfilled.)
The important idea, however, is to understand that Jesus was speaking to a particular audience when he predicted these things. He was not speaking to 21st century Christians, He was speaking to first century Jews. And in the presence of these Jews, in roughly the year 30 AD, he pronounced that all his predictions would come true before they had all died. It seems relatively clear, then, that we ought to look for the fulfillment of these predictions to occur within the lifetime of his audience. The Preterist position, I would submit, offers the clearest, plainest, and most literal understanding of Christ's words possible here in Matthew 24.
A little nugget from our good buddy, John Calvin may be apropos regarding verse 34:
Though Christ employs a general expression, yet he does not extend the discourses to all the miseries which would befall the Church, but merely informs them, that before a single generation shall have been completed, they will learn by experience the truth of what he has said. For within fifty years the city was destroyed and the temple was rased, the whole country was reduced to a hideous desert, and the obstinacy of the world rose up against God. Nay more, their rage was inflamed to exterminate the doctrine of salvation, false teachers arose to corrupt the pure gospel by their impostures, religion sustained amazing shocks, and the whole company of the godly was miserably distressed. Now though the same evils were perpetrated in uninterrupted succession for many ages afterward, yet what Christ said was true, that, before the close of a single generation, believers would feel in reality, and by undoubted experience, the truth of his prediction