Undoubtedly even the days which have been designated in our generation as commemorations of the Holocaust will quickly be forgotten, and the recollection of even this great tragedy joined to the accumulation of national mourning on the Ninth of Av.
The legend that the Messiah was born on Tisha B’Av, at the very time of the Destruction, is a key to understanding one aspect of the problem of the destruction and the notion of redemption.
For redemption to take place, the repair of the various individual destructions alone is insufficient.
Even if the entire people of Israel were to return to its land, this would be insufficient for the redemption of the Destruction.
Furthermore, even the building of the Temple in and of itself could not repair that which had been damaged in the course of the generations.
Only the Messiah – who will bring redemption to the world on a higher plane and in a more complete fashion than ever before possible – can undo the Destruction.
Redemption is not simply a return to the situation as it previously existed.
Restoration is only a small part of the scheme of redemption.
The redemption of the Jewish people must be accompanied by a qualitative change that affects the entire world.
Only a redemption that rises above the sufferings of two thousand years, that brings the Jewish people – and the entire world – to a higher level of existence, this alone is full reparation for the Destruction.”
–Rabbi Adin Steinsaltz
From an essay by Rabbi Adin Steinsaltz “Tisha B’Av: Destruction and Redemption”