The Gemara in Maseches Rosh HaShana (18b) says that there are three categories regarding the four fasts (of Asarah b’Teves, Shiva Asar b’Tamuz, Tisha b’Av, and Tzom Gedaliah) : 1) when there is gezeiras malchus (persecution) all four fasts are obligatory as fasts, 2) when there is no gezeiras malchus but also not shalom only Tisha b’Av is obligatory, and the rest are optional, 3) when there is shalom all four are Yamim Tovim. These different situations directly impact the status of the four fasts. However, it is a machlokes Rishonim regarding how to understand this.
Rashi holds that the time period of the second Beis Ha’Mikdash was considered a time of shalom and therefore all four “fasts” had the status of Yomtov, even Tisha B’Av. Nowadays, it depends. When it is a time of persecution, it is obligatory to fast on these four days, and when it is a time that there is no persecution, three out of the four are optional; and just Tisha b’Av remains obligatory since it is a day of extreme sorrow. That is how most Rishonim hold, just that they add that Klal Yisrael has already accepted upon themselves to fast nowadays even when there is no persecution.
Within this approach, there is the opinion of the Ramban who holds that, essentially, there is no difference between Tisha b’Av and all the rest. Therefore, holds the Ramban, when it is a time of persecution – which makes it a full-fledged obligation (and not just a minhag) – the other three fasts are a full twenty-four hours and all five inuyim apply, just like by Tisha b’Av. The reasons, maintains the Ramban, that nowadays we do not observe the other three fasts on the same level of severity as Tisha b’Av is that since it is not a time of persecution, they are voluntary. Although Klal Yisrael indeed accepted upon themselves to observe them, that minhag was only to observe them without their full severity. The Gra seems to concur with this opinion of the Ramban.
The Rambam, though, says differently. If you read it carefully, it is clear that the breakdown according to the Rambam is as follows: 1) the time of the first Beis Ha’Mikdash was considered a time of shalom (when all four “fasts” were Yamim Tovim), 2) the time of the second Beis Ha’Mikdash was considered a time of no persecution but also not shalom, and 3) nowadays, since we live with the churban, it is inherently always considered time of persecution.
So we see from the Rambam two chiddushim: number one, that during the time of the second Beis Ha’Mikdaash, Tisha b’Av was observed as a fast! This is corroborated by the fact that the Rambam says this explicitly in Pirush Ha’Mishnayos (in the first perek of Rosh Ha’Shana). But even without that, it is clear from the Rambam in Yad Ha’Chazakah that this is how he holds, if you read it carefully. This demands some sort of explanation. Why would Tisha b’Av already be considered a day of such extreme sorrow even before the second Beis Ha’Mikdash was destroyed? It is possible to posit that it is because the second Beis Ha’Mikdash was not on the level of the first Beis Ha’Mikdash (as the Gemara in Yoma 21b says that 5 things were lacking in the second Beis Ha’Mikdash: the aron ha’kodesh, the keruvim, the Heavenly fire, hashraas ha’Shechina, and ruach ha’kodesh –Editor-). Therefore, it was still necessary to mourn the loss of the first Beis Ha’Mikdash. It is worthwhile to note that the straightforward reading of the Gemara in Maseches Taanis
Chiddush number two of the Rambam is that he holds not like the Ramban who says that when it is a time of persecution the other three fasts are just as severe as Tisha b’Av and have all the same restrictions. How do we see that the Rambam does not agree with this? Because the Rambam says that nowadays it is inherently always a time of persecution – which means all four fasts are totally mandatory and not subject to minhag – and yet he does not assign the other three fasts the same halachos as Tisha b’Av. Only Tisha b’Avis a full 24 hours and has all five inuyim, but the other three fasts only are during the day and do not have all the other restrictions.
There is a well-known statement of the Maggid Mi’Mezeritch that the Shechina is in exile during the period of the Three Weeks, and that it is about this that the pasuk in Eichah says, “all of her pursuers caught up to her bein hametzarim”. Meaning, during the time of Bein HaMetzarim (the Three Weeks), it is relatively easy to attain connection with the Shechina. This concept is echoed in the Maharsha’s statement in Maseches Bechoros (daf 8) that the 21 days of the Three Weeks correspond to the 21 days that commence with Rosh Ha’Shana and conclude with Shemini Atzeres.
(Audio recording and notes of Reb Danny Fast)
Provided courtesy of VayigdalMoshe.com