There is a famous story that one Tisha B’Av as Napoleon was walking through the streets of Paris he heard bitter wailing coming form inside a building. When he walked in he saw a group of Jews sitting on the floor saying kinos and crying. He asked them, “Why are you crying?” They answered that, “Jerusalem was overrun and the Temple was destroyed.” Napoleon thought for a minute and then told the Jews, “Do not to worry it is just an untrue rumor. I know for a fact that all is quiet in the Middle East.”
The group then explained to him that they are mourning an event that took place 1600 years earlier. An astounded Napolean replied, “If you are still crying 16 centuries later I have no doubt that one day your temple will be rebuilt.”
Napoleon’s comments give logical spin to the Gemara’s statement “Kol Hamishabel Al Yerushalayim Zocheh V’Roeh B’Nechamasa”. He who mourns Yerushalayim will merit seeing it rebuilt. If the determination and connection are still there after the long bitter galus we will certainly merit building the Bais HaMikdash once again. However warns the gemara, if the 2000 year long river of tears runs dry, we will be cut off and can never navigate our way back home.