Judaism, like other religions, provides guidance and rituals that help its adherents handle big life-cycle events. One of the biggest events we all have to deal with is mourning -- dealing with the death of those near to us and our resulting emotions. While Judaism focuses less on death and the afterlife than many other religions, there are many laws and traditions around death and mourners.
Shiva is the first seven days after a death. Traditionally during this time, the immediate family refrains from many normal activities. They stay home. Friends and family bring food to relieve them of the the daily responsibilities of food preparation. Family members may tear their clothing or symbolically wear a ribbon that they tear. A short shiva prayer service may be held at the home daily. The visitors to the house are there to serve and help the family rather than as guests.
The First Year
Caring for the mourners, food not flowers, light a candle, covering mirrors, what you don't ask
memorial, donations, unveiling yartzeit candle
... between different Jewish traditions ... between Judaism and other religions ?
Unlike the common Western Christian custom, Jews do not usually bring or send flowers to the mourners, the funeral or gravesite. Food is brought to the house of the mourners.