There are numerous prophecies through God's servants that have come true, giving us reason to believe the rest will also be fulfilled. To save time, here's some of those prophecies: http://www.netbiblestudy.com/00_cart...leprophecy.pdf

Now prophecies can't be absolutely explicit unless they are for short term use. Long term prophecies have to be veiled enough to keep people from trying to change events and corrupt the prophecy.  There were a lot of people who were second-guessing the messianic prophecies at approximately the right time, trying to foist themselves off as the messiah. A lot of boys were named "Jesus" at that time. But only the true Jesus fulfilled all the prophecies and performed the signs & wonders.

If explicit prophecies had been written and put in a time capsule, the anti-believers would declare they were spurious because the custody of the evidence had been broken. Some people have tried to do that with portions of the Bible.

So the long term prophecies have to be seen as fulfilled in the present or in retrospect. When the Great Tribulation comes, people will recognize it at that time and not lose hope that God is still in control.