Nothing in the world can oppose or weaken, G-d forbid, a manifestation or revelation of holiness to the Jewish people. * From Chapter Six of Rabbi Shloma Majeski’s Likkutei Mekoros (Underlined text is the compiler’s emphasis.)
Translated by Boruch Merkur
2. […] On one’s birthday “his mazel rules.” Therefore, Tisha B’Av [the birthday of Moshiach] – when the mazel of Moshiach Tzidkeinu rules – is an auspicious time for the true and complete redemption.
The preeminence of Moshiach on Tisha B’Av also finds expression in practical Torah law: It is stated in the writings of the Arizal that we recite Nacheim (“verses of nechama, consolation”) on the day of Tisha B’Av at Mincha, “for at Mincha time on Tisha B’Av was the birth of Moshiach, who is called Menachem.”*
When Tisha B’Av occurs on Shabbos (as it does this year), and the fast (and the saying of Nacheim) is deferred until Sunday, then only the undesirable aspects of Tisha B’Av are pushed off. That is, the fast and the ascetic customs and mourning, etc. However, the positive and desirable aspects – the fact that Moshiach, savior of the Jewish people, was born on this day – are not deferred nor diminished when Tisha B’Av occurs on Shabbos. In fact, the positive aspects are even more overt and more powerful on Shabbos.
The reason is as follows. All worldly matters – including the loftiest aspects of Seider Hishtalshlus (such as angels and even the ten S’firos, etc.) – were created “for the sake of the Jewish people” (and “for the sake of Torah”) (though “the thought of the Jewish people” “preceded the Torah.” (Indeed, Torah was giving for the sake of the Jewish people, as it says, “Command the Jewish people,” “Speak to the Jewish people.”)). Nothing in the world – including an established, set time (which is dependent upon the orbit of the sun, the moon, and the constellations), all of which were created for the sake of the Jewish people – can oppose or weaken, G-d forbid, a manifestation or revelation of holiness to the Jewish people. Certainly this principle includes such a fundamental concept for Jews as the birth of Moshiach and the preeminence of his mazel (on Tisha B’Av).
NOTES:
*Footnote 17: And this is the reason why we recite Birchas HaLevana when Tisha B’Av goes out, “for Moshiach was born on Tisha B’Av” (Pri Eitz Chayim, Shaar 23, “Kavanas Tisha B’Av U’Vein HaMeitzarim,” end; Mishnas Chassidim, end of Meseches Tammuz and Av).
(From the address of Shabbos Parshas D’varim, Shabbos Chazon, Tisha B’Av (nidcheh), 10 of Av (before Arvis), and 11 Av; Seifer HaSichos 5751, pg. 722)