398. Gone But Not Forgotten: The obligation to carry out the laws of impurity of the deceased
This is the law regarding one who dies in a tent… (Numbers 19:14)
We are commanded to follow the entire body of laws pertaining to ritual impurity as caused by a human corpse, as spelled out over the next few verses: anyone in the same building as the deceased will be unclean for seven days (verse 14); every uncovered container under the same roof will be unclean (verse 15); anyone outside who touches a body, a grave or a human bone will be unclean for seven days (verse 16).
The reason we must observe the laws of the impurity of the deceased is that a corpse is avi avos hatumah – “the great-granddaddy of ritual impurity” – that is, the greatest source of ritual uncleanliness. Nothing is of a higher degree of tumah than a deceased human being.
This mitzvah applies to men and women in all times and places. In the Talmud, it is the subject of tractate Ohalos. It is codified in the Mishneh Torah in Hilchos Tumas Meis. This mitzvah is #107 of the 248 positive mitzvos in the Rambam’s Sefer HaMitzvos. As mentioned in Mitzvah #159, the Ramban (Nachmanides) does not include the laws of ritual impurity in his list of the 613 mitzvos; likewise, this mitzvah is not included among those that might be observed today in the Sefer HaMitzvos HaKatzar of the Chofetz Chaim.