A fast day that is established on the anniversary of a calamity that led to our exile is an eiss ratzon, a day of special divine favor. The fast, prayers, and activities of the day are designed to arouse us to teshuvah that will lead to the repair of that which was destroyed, with the arrival of the final redemption. This power is greatly amplified on today's fast, because it does not mark an incident of destruction. Instead, it marks the day on which the Babylonian army laid siege to Yerushalayim. The holy city and even its outer walls remained completely intact. At that point, the siege was a last call for teshuvah to avoid the destruction. So it is not a day of destruction, but quite the opposite: a day of avoiding exile. As such, our power to do teshuvah and end our exile is far greater today. Let us seize this powerful opportunity to bring the final redemption!