1. The Jews of the first generation of the Desert ceased to die, indicating that the punishment for the Sin of the Spies was complete;
2. All of the Tribes were permitted to once again marry into the Tribe of Binyamin, following the sin of the Pilegesh at Giv'ah;
3. Hoshea ben Elah removed the roadblocks which were erected by Yeravam ben Nevat to prevent the Jews from going to the Beis Ha-Mikdash for the Yomim Tovim;
4. The Romans granted permission to bury the dead Jews of Beitar;
5. All wood to be used for the Mizbayach was finally cut for the next year's sacrificial service.
The above all represent cause to celebrate, but is there any common theme which unifies them into Tu B'Av? What is the underlying quality of this special day?
The above all represent a reprieve from suffering and vulnerability. The first four events described above reflect the end of a period of anguish. Although salvation was not yet at hand, a sense of relief was obtained. Even completing the cutting of wood for the Beis Ha-Mikdash symbolized an escape from potential affliction, as the enemies of our people traditionally tried to hinder sacrificial service by blocking the supply of wood. Thus, filling the stock of wood for the new year of Avodah was a great relief and an escape from vulnerability vis a vis interrupted Mikdash service.
Still, how does the relief achieved on Tu B'Av reflect or relate to the day's traditinal simcha as depicted in the Gemara? (The Gemara relates that Yom Kippur and Tu B'av were the happiest days of the year, as they portray the nation's atonement. [On Tu B'Av, the atonement was that of Hashem forgiving the Sin of the Spies, indicated by the cessation of death among the Generation of the Desert.]) Does the respite of Tu B'Av in any way connect with the day's joy?
Tu B'Av comes on the heels of Tisha B'Av, which represents our spiritual low. On Tisha B'Av, we sink into the abyss of loss of the Batei Mikdash and a sense of disconnection with God. Tu B'Av is the beginning of the reversal of this state. Although the historical events of Tu B'Av are far from true salvation, they mark a turn-around in Jewish destiny, indicating that the worst is behind us and that we are now back on the way to an eventual restoration of our relationship with Hashem and the return of His glory to the world. This projected restoration and drawing near to God are the theme of Tu B'Av, and the atonement contained therein reflects the relationship with Hashem which begins to be renewed on this momentous day.