Chassidut, with its focus on joy in the service of G-d, did not agree to turn the days of Bein HaMetzarim (the Three Weeks of mourning) into days of sadness and depression. Instead of focusing on mourning the destruction, the aim was to fill hearts with longing for the Redemption.
During the days of Bein HaMetzarim, Chassidic communities increase their focus on the topic of the Redemption and the anticipation of the rebuilding of the Third Temple. The Lubavitcher Rebbe called for studying during these days the sections of the Torah related to the Mishkan and the Temple: starting with the Written Torah (Terumah and Vayakhel-Pekudei; Ezekiel chapters 40–43), continuing with the Oral Torah (Tractate Middot), and on to halacha (Rambam’s Laws of the Temple) and Chassidic teachings on the subject of the Temple.
In the Book of Ezekiel, G-d tells Ezekiel, "let them measure its design," which means that the Jewish people should actively delve into the study of the measurements and dimensions of the Temple.
The Midrash tells us that Ezekiel said to G‑d: "We are now in exile, let us first go out of exile and then we will learn the laws of the Temple."
G‑d responded: Just because My children are in exile, does that mean that the building of My House should cease? That can't be! Let them learn the laws of the House and in this way, they will do them.
The Midrash explains this as, "I will consider it as if they were dealing with the construction of the House." From here it is understood that, though the Third Temple will be built by G‑d, still it is also through our efforts. Through learning about the Third Temple, we help build it.
In the year 5751 (1991), the Rebbe added:
"Since we are standing on the threshold of the Redemption, which is coming immediately, it is understood that the study of the laws of the Temple this year must be in a completely different way:
“Firstly, the study is not due to intensified mourning or effort to correct the lack caused by the destruction of the Temple, but rather (even if there had been no destruction) it is driven by yearning and desire for the greatness and perfection of the Third Temple, about which it is said: ‘The glory of this latter House will be greater than the first—a greatness that never existed before (not in the Second Temple, not in the First Temple, and not even in the Mishkan that Moses built)...
“More importantly, the learning must come with the absolute certainty that this is not just a (theoretical or academic study) “halacha for the Messianic era”—but a practical, actionable halacha, ready to be implemented in the very next moment. This is because the ‘future Temple that we await is built and complete (already now Above) and will be revealed and descend from Heaven’ in an instant!
“Just as we’ve recently spoken about the special increase in Torah study related to the Redemption and Moshiach—not (just) as a segulah (spiritual merit) to hasten the Redemption, but primarily as a way to begin actually living with the ideas of Moshiach and the Redemption, to ‘live with the times’ of the Messianic era... and to practically conduct ourselves—in thought, speech, and action—in a way that aligns with this special time, as we stand on the threshold of the Redemption and can point with our finger and say: ‘Behold, he (the King Moshiach) is coming!’"
