במדבר, פרק י״ט, פסוק ט״ז

The laws of ritual impurity regarding a human corpse extend beyond enclosed structures to include sources of impurity found in an open environment. In an exposed, roofless area, impurity is generally transferred through direct physical contact with the deceased. This contrasts with the impurity of a tent, where simply sharing the same covered space as a body is enough to render a person impure [רשב״ם, חזקוני, ביאור שטיינזלץ].

The emphasis on an open space carries deeper implications. Some commentators understand this to include the cover and sides of a coffin. Even though these are not the body itself, touching them transfers impurity just like touching the corpse [רש״י, ברטנורא, גור אריה]. Others note that the requirement for the impurity to be in a visible, open space excludes a deceased fetus still in its mother's womb. Because it remains hidden and absorbed, it does not transfer impurity until it enters the world [הכתב והקבלה, מלבי״ם, אדרת אליהו]. Additionally, the open environment can actually create a unique form of tent impurity, which occurs when a person physically leans over and overshadows a corpse in a field [רש״ר הירש, העמק דבר].

A distinction is made between someone killed violently and someone who dies a natural death [ביאור יש״ר, הכתב והקבלה, חזקוני]. While a sword is used as the standard example of a violent end, the law applies equally to someone killed by a stone or a fist [רמב״ן, רבנו בחיי, הטור הארוך]. The specific mention of a sword introduces a fundamental rule in the laws of impurity: metal vessels that touch a corpse take on the severe status of the corpse itself. They receive the highest degree of impurity, capable of making people and other objects impure for seven days. This extreme severity for metal vessels, however, is limited to impurity transferred by touch rather than by sharing a roof. If they transferred impurity merely by being in the same room, priests would be entirely prevented from entering any house containing an impure metal object [רמב״ן, רבנו בחיי, תורה תמימה].

An alternative approach suggests that the reference to someone killed violently actually describes a limb severed from a living person, provided it has enough flesh to potentially heal. In contrast, the reference to a natural death applies to a limb severed from a corpse [תורה תמימה, אדרת אליהו, רלב״ג].

Impurity is also contracted from human bones that lack flesh, regardless of whether they are moist or dry. The only exceptions are detached teeth, hair, and nails, which do not transfer impurity [תורה תמימה]. This severe degree of impurity applies to a significant quantity of bones, such as a specific volume measure, an intact skull, a spine, or the majority of a human skeleton. These transfer impurity through touch, carrying, and overshadowing, exactly like a complete corpse. A small bone, however, only transfers impurity through touch and carrying, but not through overshadowing [רלב״ג, תורה תמימה, אדרת אליהו]. The underlying reason for the severe impurity of human bones is to create a firm boundary between the living and the dead. This barrier prevents people from keeping the bones of their relatives out of affection, while also protecting the deceased from degradation, ensuring that human skin and bones are never used to craft tools or rugs [חזקוני].

Finally, the laws address a human grave [אבן עזרא]. Even a completely sealed grave with no airspace inside transfers impurity. The impurity is viewed as breaking through and rising upward, meaning that a person walking directly over the grave immediately becomes impure, even without any direct physical contact with the body below [תורה תמימה, אדרת אליהו, רלב״ג].