We are taught in today’s daf (Moed Katan 23a-b) that there was a dispute between בני יהודה (the Judeans) and בני גלילא (the Galileans) about whether יש אבלות בשבת – ‘there is mourning on Shabbat’ or אין אבלות בשבת – ‘there is no mourning on Shabbat’.
It is noteworthy that from the Gemara alone it is not clear which community held which position. But as Rabbi David Yoel Weiss helpfully points out in his ‘Megadim Chadashim’ that we are taught at the end of Chapter 10 of Massechet Semachot that ‘in Judea, they greeted mourners [on the Shabbat] to demonstrate that there is no mourning on the Shabbat’ – thus serving to clarify that בני גלילא (the Galileans) held that יש אבלות בשבת – ‘there is mourning on Shabbat’, while בני יהודה (the Judeans) held that אין אבלות בשבת – ‘there is no mourning on Shabbat’.
In terms of contemporary Jewish practice, we rule that there is no public mourning on Shabbat, while on the question of greeting mourners on Shabbat – like many other aspects of the laws of mourning – the answer is dependent on local custom (see Yerushalmi Moed Katan 3:5, Shulchan Aruch Yoreh Deah 385:3) with some communities doing so, and others not doing so.
Today, our overreliance on halachic handbooks (which often lack details or sensitivity to local custom), as well as our underappreciation, or lack of sensitivity, or lack of interest in preserving local custom, means that most people just ‘go with the flow’ – notwithstanding the various halachic inconsistencies that can emerge from such an approach. Still, today’s daf serves to remind us that while we speak of ‘the laws of mourning’, many of these are – in fact – ‘customs of mourning’ which differ, often significantly, from place to place.