Moed Katan 23B

יש אבילות בשבת, והני אמרי: אין אבילות בשבת.

There is some mourning on Shabbat, i.e., with regard to mourning rites that can be observed privately in the mourner’s home and will go unnoticed by other people; whereas those say: There is no mourning on Shabbat at all.

מאן דאמר יש אבילות בשבת, דקתני ״עולה״. מאן דאמר אין אבילות בשבת, דקתני ״אינה מפסקת״.

The Talmud explains: The ones who said that there is some mourning on Shabbat rely on that which is taught, that Shabbat counts as one of the days of mourning, implying that some degree of mourning applies on that day. The ones who said that there is no mourning on Shabbat at all base this on that which is taught that Shabbat does not interrupt the mourning period.

אי סלקא דעתך יש אבילות בשבת, השתא אבילות נהגא, אפסוקי מיבעיא?

The latter argue as follows: If it should enter your mind to say that there is some mourning on Shabbat, there is a difficulty, for now that it has been stated that actual mourning applies on Shabbat, is it necessary to teach us that this day does not interrupt the mourning period? Rather, the conclusion must be that there is no mourning on Shabbat whatsoever.

ואלא הא קתני ״עולה״! איידי דקבעי למיתנא סיפא ״אינן עולים״, תנא רישא ״עולה״.

The Talmud asks: But isn’t it taught in the Mishnah that Shabbat counts as one of the days of mourning, implying that it is just like the other days of mourning, and at least some mourning rites are practiced on it? The Talmud answers: Since the Mishnah wished to teach in the latter clause that the days of a Festival do not count toward the requisite days of mourning, it taught also in the first clause that Shabbat counts as one of the days of mourning, although no mourning rites are practiced on it.