As noted in Moed Katan, two of the ways the period of mourning is continued after one “gets up from shiva” is by refraining from having one’s hair cut (this generally includes shaving one’s beard, although there are certain exemptions that can be discussed with one’s rabbi) and by not wearing new or even fresh clothing. Additionally, mourners recite the Mourner’s Kaddish and avoid listening to music and attending celebrations such as weddings and bar/bat mitzvahs, although they may stop by to wish the celebrants “Mazal Tov.”
In the event of a Jewish holiday other than Purim or Chanukah (which are both post-Biblical), the mourning period ends in honor of the festival, whether or not the 30 days have been completed.
The count of thirty days is derived from Deuteronomy 34:8, which records that the Children of Israel wept for Moses for 30 days after he died. At the conclusion of the shloshim, it is customary to make or host a siyyum (special celebration observed upon completing any set amount of Torah study) in honor of the deceased.
Copyright © 2014 NJOP. All rights reserved.