I don't get what you mean MP. Luke 21:8 and my comment have nothing to do with Paul.
Perhaps you mean that Jesus words only applied to the 'then and there', the people of his time with the destruction of Jerusalem in mind? Like when Jesus said 'this generation' he meant the destruction of Jerusalem would come in the lifetime of those alive at that time. I agree with that. I think it is highly likely that any prophetic words Jesus used about 'destruction' related to the fall of Jerusalem.
Jehovah's Witnesses however apply Luke 21 and Matthew as having a major fulfillment in our modern day (despite there being no precedent in the scriptures for minor / major fulfillments of prophecy). From this JW view, in amongst Jesus' warnings about the time of the end, he said not to follow after people going around saying "I am Jesus, I am his representative, I come in his name, I speak for him, the end is coming!" JWs of course apply this to other religions and small time groups who tout the end times. They seem oblivious to the fact that for more than 100 years they themselves have been going around saying that they speak on behalf of Jesus as his representative, and have been throwing out dates for the end, or constantly harp on about it being 'soon' thus proving themselves to be exactly the people Jesus warned his disciples not to follow.