Judaism has long understood the psychology of grief and mourning. Since the time of the Talmud there has been a structured and defined process of mourning for our loved ones. We move through a series of phases allowing us to work through our feelings of sadness and loss, and through the commemoration of Yahrzeit (the anniversary of death) and Yizkor יזכר (the service of memory on Yom Kippur יום כפור, Shmini Atzeret שמיני עצרת, Pesach פסח, and Shavuot שבועות) the phases never end.
The first phase takes place from the moment of death until the funeral is concluded. This period is known as aninut אנינות, and the major focus is on preparing for the funeral. There are no specific mourning rituals or prayer services, these begin at the culmination of the funeral as the mourner enters into the period of shiva שבעה.
Before considering why we sit shiva it is important to note that Judaism specifies that there are seven relatives for whom we are supposed to mourn: these are mother, father, spouse, sister, brother, son, and daughter). There is also a tradition that those you mourn for, you mourn with; in this way if a grandparent passes away you may consider yourself a mourner through your parents.
In the Torah we have the idea of taking time, immediately after the death of a loved one, for mourning. When Sarah dies, Abraham mourns for an undefined period of time ‘standing up from before his dead’ (Genesis 23:3). When Jacob believed Joseph had been killed he ‘tore his clothes, put on sackcloth and mourned his son for many days’ (Genesis 37:35). And when Moses died the people of Israel mourned and ‘wept for Moses in the plains of Moab for thirty days’ (Deuteronomy 34:8).
The source of a period of seven days of mourning may be related to Jacob’s death. Joseph and the family return to Israel for Jacob’s burial and we read ‘he made a mourning for his father seven days’ (Genesis 50:10). By the time of the Talmud the idea of a period of seven days of mourning had been established.
We may also consider other reasons why we are told to take seven days for this first, intense period of mourning. In the Torah seven is a very important number, and it appears to denote a complete period of time; first with the story of creation, but then also with the seven days for purification rituals, seven days for Pesach and Sukkot סכות. If there were a lucky number in Judaism it would be the number 7. By instituting seven days for shiva the Rabbis also ensured that the mourner experiences a full week without the person they have lost. This may be related to the idea of the person’s world needing to be recreated without their loved one.
Shiva is the most intense period of mourning, and traditionally during that week the mourners remain at home and sit on low stools (this is a way of reinforcing how the person is feeling through their outward appearance). During this week the mourner is exempt from the regular daily responsibilities, and they are supposed to take time to mourn and reflect upon their loss. Traditionally the first three days are for the most intense mourning.
It is a mitzvah to visit a shiva house to provide comfort to the mourners. This commandment is also important, because with the start of shiva the mourner begins the period of reciting the Kaddish קדיש in memory of their loved ones. The Kaddish is one of the prayers which traditionally requires a minyan מנין (10 adult Jews) in order for it to be recited; the minyan also allows for the full prayer service to be conducted in their home.
At the conclusion of shiva a mourner enters the period of sheloshim שלושים (literally meaning thirty, corresponding to the number of days of this period). During this time the mourner returns to work, but they continue to say the Kaddish and traditionally a number of mourning rituals persist (no entertainment and men not shaving).