Commemoration of the Destruction and Commemoration of the Mikdash
Our Sages instructed that instances of joy should include remembrances of the destruction of the Temple, to remind us that our joy is not complete.
When we build a house we leave a small bit of wall unpainted; at a wedding we break a glass as a reminder of sorrow. These observances are called ZEKHER LACHURBAN "commemorations of the destruction" (SA OC 560).
Although the Temple in Yerushalayim has been desolate for almost two thousand years, since the year 72CE, its memory is very much alive for the Jewish people. We remember the Temple in our daily prayers, in our periodic fasts, and also in various customs, mentioned in this chapter, which continue the mourning over the loss of the Sanctuary throughout the year, and especially on happy occasions.
These customs emphasize that even when we have moments of special joy, our simcha is not complete as long as the Temple is in ruins. Remembering the destruction at happy times is also important because the exhilaration of joy is liable to make us forgot our mourning, even if we are normally conscious of it.
The various customs commemorating the destruction of the Temple were originally instituted by Rebbe Yochanan ben Zakkai immediately following the destruction itself. Alongside these customs, Rebbe Yochanan ben Zakkai instituted other decrees, which are called ZEKHER LAMIKDASH - a commemoration of the Temple.
For instance, the previous custom was that the lulav was waved only on the Sukkot holiday itself. The lulav was taken during the intermediate days only in the Temple. Rebbe Yochanan ben Zakkai instituted that the lulav should be taken throughout the holiday every- where (Mishna Rosh HaShana 4:3). Another example: the new grain crop (chadash) used to become permissible when the omer offering was brought. But when there is no Temple and no offering, it becomes permissible immediately on the day following Pesach. Rebbe Yochanan instituted that it was necessary to wait until the end of the day, to demonstrate that weare still waiting for the Temple to be built (Mishna Menachot 10:5).
Why was there a need for two distinct kinds of decrees - some recalling the destruction of the Temple, and others recalling the Temple itself? One answer is that at that time Rebbe Yochanan actually faced a double challenge. While the disappearance of the Temple created a need to commemorate it, so that future generations would not forget the importance of the Beit HaMikdash, there was paradoxically an opposite challenge as well: to help people forget the Temple.
At the time of the destruction of the Second Temple, the Jewish people had not been without a Sanctuary for more than a thousand years, except for a short period at the beginning of the Babylonian exile, when there was a Divine promise that the exile would be limited to seventy years. Profound despair gripped the people, as many Jews did not believe that the Jewish religion or even the Jewish nation could survive without the Temple (See Bava Batra 60b).
Striking a balance between the need of his generation for consolation and the need of future generations for perpetuation, Rebbe Yochanan instituted two distinct kinds of decrees. One kind of decree was the ZEKHER LACHURBAN - to make sure that people remembered that Jewish life is incomplete with the Temple. But he also instituted a parallel kind of decree - ZEKHER LAMIKDASH, remembering the Temple. These laws have two purposes. First of all, they remind us that even without the Temple, life does go on. Thus, even when the Temple is destroyed, the lulav can be taken all Sukkot. Second of all, they remind us that the Temple will eventually be rebuilt; thus, we need to delay eating chadash.
In this way, the commemorations instituted by Rebbe Yochanan ben Zakkai create a delicate balance between loss, coping, and hope. On the one hand, we acknowledge that Jewish life is not "business as usual" without the Temple. However, we also recognize that even if things are not as they should be, life - including Jewish life and the joy of life - does go on. Finally, we draw hope from the certain knowledge that eventually, perhaps any moment, the Temple will be rebuilt and our full national and religious existence restored.