בנים אתם לד' אלקיכם... לא תתגודדו ולא תשימו קרחה בין עניכם למת כי עם קדוש אתה לד' אלקיך
The Torah appears to be giving us a straightforward mandate: do not grieve excessively. When someone dies, his relatives should not mutilate themselves out of grief. As a holy people we do not conduct ourselves in such a manner. Chazal, however, see a different meaning for Lo sisgodedu. The sisgodedu is derived from agudah, group/gathering of people. They interpret Lo sisgodedu as, “Do not form factions.” Hence, we learn that forming factions is prohibited. This plays itself out practically when two batei din, courts of law, are in one town; one rules in accordance with the decisions rendered by Bais…