Four days a year Jews fast and mourn, commemorating different historical events of the destruction of the Holy Temple.  The 17th day of Tammuz is one of the four days, and it begins a three week period of limited mourning that climaxes with Tisha B'Av, the day of the destruction of the bothTemples.  These four days of fasting are found in the prophet Zechariah.  Consistent with Judaism's optimism, the biblical references about the four days, including Tisha B'Av are not cited as directives to fast and mourn.

Instead, they are stated in a postive context, looking to the Messianic future, when these four fast days will become days of celebration, "The four fasts will become days of joy and happiness, holidays of redemption, and feasts for the House of Judah", (Zechariah 8:19).  Thus, Tisha B'Av was destined to be part of our Halachic tradition, but not as a day of eternal mourning.  Rather, it is a temporary day of mourning, until it becomes a permanent day of joy in the Messianic Era. In Eicha, Tisha B'Av is called Moed (Festival) (1:15, 2:22). That is why we don't say Tachanun and Selichot on Tisha B'Av (S.A. 559:4).  What are the signs of the approaching Messianic Era?  The Talmud states that the Jews returning from exile and the turning of the land of Israel green is the key sign for the beginning of the Redemption.  "There is no more clearer sign then when the Land of Israel gives its produce abundantly, then the end of the exile is near, (Sanhedrin 98B, Rashi).

For close to 2,000 years our land rejected all would-be conquerors and remained desolate.  The Sifra  explains, that the Torah's curse of the land during our long exile, "I will make the land desolate", (Parshas Bechukosai) is actually a blessing in disguise.  Because we didn't have to worry when we went into exile that our enemies would settle our land.  Therefore, the greening of Israel is a clear signal that G-d's decree of "desolation" for the land is over and the Redemption is near.  The Land of Israel had to go into "hibernation", waiting for us, her children, to return from exile.

The prophet Jeremiah saw the coming Redemption of the Messianic Era and its' celebration as being an even greater event than the Exodus from Egypt. "Days are coming, says G-d, when it will no longer be said, as G-d lives Who took Israel out of Egypt, but rather, as G-d lives, Who took Israel out from all the lands where G-d dispersed them" (Jer. 16:14,15). We are presently in the dawn of the Messianic Era.  If Messiah should arrive before Tisha B'Av, then we will be feasting instead of fasting.

The Talmud tells us that when the Temple was set on fire on Tisha B'Av, the Kohanim ascended to the roof and taking the keys of the Temple, threw them towards Heaven. They cried, " Oh G-D, we were not worthy of having these keys. You keep them until a generation shall arise that is more worthy to possess them than we are" (Yerushalmi, Shekalim 6:2).

According to the Rebbe of Chabad, we may be that generation, to whom G-D will once again entrust those keys. Let us learn the lesson of Tisha B'Av, by turning Sinat Chinam into Ahavat Chinam, so that the keys of the Temple may be returned to us.