One of the main things we learn in Mark 13 is that Jesus isn't bluffing when he talks about judgement day. He said to his increasingly bemused disciples that the massive 500 year old temple in Jerusalem would be destroyed within one generation. Forty years later in AD 70 it was systematically torn down by the Romans during an attack on Jerusalem that has gone down in history as one of the most shocking examples of human suffering ever.

I think it's worth getting a feel for what it was like to be in Jerusalem in AD 70 so here's a quote from a modern (athiest) historian based on an eye-witness account:

"Around the walls, there were gruesome scenes that msut have resembled hell on earth. Thousands of bodies putrefied in the sun. The stench was unbearable. Packs of dogs and jackals feasted on human flesh. In the preceding months, Titus had ordered all prisoners or defectors to be crucified. Five hundred Jews were crucified each day. The Mount of Olives and the craggy hills around the city were so crowded with crucifixes that there was scarcely room for any more, nor trees to make them" (Jerusalem: the biography, Simon Sebag Montefiore, 2011).

Would the original disciples have found it easy to believe Jesus' prophesy of this terrible judgement that was to happen in their lifetime? Surely their natual response would have been to doubt such an outlandish suggestion, just as our temptation is to doubt that the Son of Man will return on the clouds of heaven, perhaps in our lifetime, perhaps even today?

When we struggle to believe that Jesus will come again at any moment to wrap up creation, we should think carefully about on the force of Mark 13. In it he prophesies both the destruction of the temple and the end of the world. The temple was destroyed exactly as he said. So let's not be fooled into thinking the final judgement day is unlikely because the world hasn't changed for 2000 years (or longer). The destruction of the temple within a generation was highly 'unlikely' based on that kind of thinking, but history has shown us that Jesus' words will certainly come to pass. He's not bluffing.