Moed Katan 21 - For whom to mourn

A priest (Kohen) must not go to the cemetery. He must also avoid contact with the dead bodies or being under the same roof. Even today, when people cannot observe the purification with the ashes of a red heifer, the priests still must follow these laws.

However, when his close relatives die, the priest must, on the contrary, become impure and take part in the funeral. Who are these close relatives? - His mother and father, his son and his daughter, his brother, his unmarried sister, and his wife.

The same list of seven close relations applies to ordinary people who mourn a relative. How does one express his mourning? He makes ritual clothes rending, does not work, does not bathe, does not engage in marital relations, does not wear shoes, does not wear tefillin, and does not study Torah. 

Art: Artist`s Parents, by David Wilkie