Mat 24:14 And this gospel of the kingdom shall be preached in all the world for a witness unto all nations; and then shall the end come.

Alternative: And the reward for good news of the rule shall be proclaimed as evident to all people and at that time our goal is reached.

Taken with the previous verse, Christ is saying that those who hold to their purpose will survive as rocks of stability in a confused world. Their survival will be seen as a reward for trusting in the good news of God's rule. Once everyone sees that the rules that Christ is teaching work, the purpose of everything is met.

This is a message, not of an end of the world and destruction, but of a goal that transcends the troubles that we or the world suffers at any point in time. Those troubles, war and disasters, are inevitable. What is important is not the disasters, but how people react. When the crowd follows one new prophet after another, the world just gets worse and more lawless. However, the remnant, those who understand the good news, are saved from all this confusion and lawlessness, seving as an example to everyone else. Eventually, everyone will recognize that those few that hold to Christ's view of the universal rule survive and are rewarded for their faith.

This view is not very different than an historical view of the survival of the Jewish people itself. The difference is that Christ is saying that the universal rule will save not just one ethnic group, and that all people will eventually recognize that it works.

Again, on an historical level, this prediction works both regarding the fall of Jerusalem, all of history since Christ, and in our personal lives.

"Gospel" is from euangelion, which originally meant "a reward for good tiding given to a messenger." It was customary to reward a messenger who brought good news in the same way that we might tip someone. It later was used to denote "good tiding" and "good news" itself.

"Preached" is from kêrussô, which mean "to be a herald," "to make a proclaimation as a herald," "to proclaim," and "to announce."

"The world" is from oikoumenê, which means "the inhabited region." It was often used to denote the civilized world as separate from the lands of barbarians.

"Witness" is from marturion, which means "testimony" and "proof."