The following entities impart ritual impurity when they are touched, carried, or one is under the same structure: a) a corpse, even a stillborn fetus whose limbs have not become attached to its body with sinews, b) an olive-sized portion of flesh from a corpse, c) an olive-sized portion of netzal, d) a limb from a living person that has the required amount of flesh, e) a limb from a corpse that has the required amount of flesh, f) the backbone of a corpse, g) its skull, h) the majority of its structure, i) the majority of the number of its bones, j) a fourth of a kab of bones in any instance, even if they do not comprise the majority of the structure of the number of the bones of the corpse, k) a revi'it of blood, and l) a revi'it of blood of "weltering blood"; twelve entities in total.
The following entities impart ritual impurity when they are touched or carried, but not when one is under the same structure: a) a limb from a living person that is lacking enough flesh to regenerate itself, b) a limb from a corpse that is lacking either flesh or bone and does not have enough flesh to regenerate itself or the bone is lacking, even if has enough flesh to regenerate itself, c) a backbone that is lacking and does not possess a fourth of a kab of bones, d) a skull that is lacking and does not possess a fourth of a kab of bones, e) a bone, even if it is the size of a barley corn, f) the earth of the nations, and g) a beit hapras; seven entities in total.
📋 Full Summary
The chapter opens with a systematic list: 12 items convey touch, carrying, and ohel impurity (including: a corpse, kzayit flesh, netzal, properly-fleshed limbs, skull, spine, majority structure/count, quarter-kab bones, revi'it blood, dam tevusah). 7 items convey only touch and carrying (deficient limbs, single bones, beit hapras earth, etc.).
4/9
Special Cases: Golel, Dofek, Rekev — and Rambam's View on Scriptural Status
A gollel and a dofek impart ritual impurity when they are touched or when one is under the same shelter, like a grave. They do not impart ritual impurity when carried. The decomposed mass of a corpse imparts ritual impurity when it is carried or when one is under the same shelter. It does not impart ritual impurity when touched. It appears to me that the ritual impurity imparted by a fourth of a kab of bones when one is under the same structure, a revi'it of blood, a limb that does not have the sufficient amount of flesh, whether from a corpse or from a living person is not of Scriptural origin, as evidenced by the fact that a nazirite need not shave his hair because of them, as we explained in Hilchot Nizirut. Nor is one liable for entering the Temple after having contracted such impurity and when a person is impure due to an impurity of Scriptural origin, he is liable for entering the Temple. Therefore I maintain that all sources of impurity from a corpse that do not require a nazirite to shave are not of Scriptural origin.
The decomposed mass of a corpse does not impart ritual impurity unless it is buried naked in a coffin of marble, glass, or the like, and it was totally intact at the time of burial. If it was lacking a limb, it was buried in its garments, or it was buried in a coffin of wood or metal, the decomposed mass does not impart ritual impurity. The rationale is that the rot of the garment or the wood and the rust of the metal will become mixed with the decomposed mass of the corpse. When any amount of earth becomes mixed with the decomposed mass of a corpse, it remains impure. These laws of rekev applies only to the corpse of one who died naturally. They do not apply to one who was slain.
⚖️ Rabbinic vs. Torah
Golel and dofek convey touch and ohel but not carrying (Rabbinically). Rekev conveys carrying and ohel but not touch. The Rambam expresses his view: the quarter-kab ohel impurity, revi'it blood, and deficient limbs are likely not Scriptural — since a nazirite need not shave for them, they cannot be full Torah-level impurities.
The decomposed mass of a corpse does not impart ritual impurity unless it is buried naked in a coffin of marble, glass, or the like, and it was totally intact at the time of burial. If it was lacking a limb, it was buried in its garments, or it was buried in a coffin of wood or metal, the decomposed mass does not impart ritual impurity. The rationale is that the rot of the garment or the wood and the rust of the metal will become mixed with the decomposed mass of the corpse. When any amount of earth becomes mixed with the decomposed mass of a corpse, it remains impure. These laws of rekev applies only to the corpse of one who died naturally. They do not apply to one who was slain.
When two corpses are buried together, a deceased's hair or nails were trimmed and then buried with him, or a pregnant woman was buried with the fetus she was carrying, the laws of rekev do not apply.
If one ground a corpse until it became a decomposed mass, it does not convey the impurity of rekev. Those laws do not apply unless it decomposes as part of a natural process.
If one ground a corpse and then left its remains until they decomposed naturally or a portion of the body decomposed while the person was alive, he died, and then the entire body decomposed, there is an unresolved doubt concerning the ruling. Hence, if a person becomes impure because of two handfuls of this rekev, he must consider himself impure, because of this unresolved doubt.
The following laws applies when there are two handfuls and more of earth that was found under a corpse or in a grave and it is not known what it comprises: whether it is rekev that imparts impurity when under the same shelter or it is merely earth that has become soiled with the netzal and the blood of the corpse. It imparts impurity when carried and when one is under the same shelter, because this mass that is more than two handfuls contains two full handfuls of rekev. It appears to me that also this impurity is a Rabbinic decree.
🪦 Rekev Conditions
Rekev (decomposed matter) only imparts impurity when the corpse was buried naked in a marble or glass coffin, completely intact. If buried in clothing, a wooden coffin, or with another corpse, hair, or nails, no valid rekev forms. Grinding a corpse artificially does not produce valid rekev — it must decompose naturally.
When a corpse was burned and its skeleton - i.e., the backbone and the ribs - is intact, it conveys impurity like an entire corpse. Needless to say, this applies if the flesh is merely charred. If, however, it is burnt to the extent that its form is destroyed, it is ritually pure. Similarly, if a miscarried embryo which had already begun to have its limbs take form was mixed with water, it is pure, because its form was destroyed.
When the flesh of a corpse has become powdery and flourlike, it is ritually pure. Similarly, the ashes of corpses that were burnt are ritually pure. Similarly, worms which come into existence from the flesh of a corpse, whether they are alive or dead, are ritually pure. We have already explained that bone marrow is considered as flesh in all instances, whether with regard to a human corpse or with regard to the carcass of an animal or crawling animal.
A person's skin is considered as his flesh. If it was processed entirely or trodden upon as is necessary for processing, it is considered as pure according to Scriptural Law. According to Rabbinic Law, however, an olive-sized portion imparts impurity like the flesh of a corpse. This is a decree, enacted so that people do not become accustomed to processing human skin and using it.
The skin that appears opposite the face of a infant when he is born, whether both he and his mother survive the birth or he and his mother die in the process of the birth, is considered as ritually pure. The rationale is that it is like a waste produce, like filth, vomit, or the like.
Every element of a corpse is impure with the exception of the teeth, the hair, and the nails, for they are replaced. While they are attached to the body, they are all impure. What is implied? When a corpse is outside a house and his hair which is attached to his body is inside, everything in the house becomes impure. Similarly, one who touches hair, teeth, or nails while they are attached to a corpse becomes impure. When the hair of the deceased was ready to be cut or his nails were ready to be trimmed, their halachic status is in doubt because they are prepared to be cut off. Therefore, one who touches them is considered as ritually impure because of the doubt. Any liquid that flows out from a corpse is pure except for its blood. Any liquid with the color of blood that flows from a corpse is impure, as we explained. Why wasn't a decree made with regard to liquids that flow from a corpse as was made with regard to liquids flowing from other impure individuals? Since everyone withdraws from a corpse, they did not feel the need to enact a decree regarding liquids that flow from it.
When a liver has decomposed, a revi'it of it imparts impurity, because it is considered like blood that has coagulated. If all the blood of an infant flows out, but it does not amount to a revi'it, it is pure even though it comprises all the blood in his body.
🔥 Destroyed Forms
If a corpse is burned but its skeleton remains intact, it is still impure like a full corpse. Powdered flesh, ashes, and worms from corpse flesh are pure. Human skin is like flesh (though if tanned, it is Rabbinically impure only). Teeth, hair, and nails while attached are impure; when detached they are pure (but if ready to be cut, status is doubtful).
If even the slightest amount of these measures are lacking, the substances are pure: a) a revi'it of blood, b) a piece of bone the size of a barley-corn, c) an olive-sized portion of flesh, d) an olive-sized portion of netzal, e) two handfuls of rekev, and f) a limb from a living person from which the slightest portion of the bone was lacking.
🔗 Combining
Touch, carrying, and ohel are three separate categories that do not combine with each other. Half an olive of flesh touched + half an olive carried = pure. But two half-olives touched simultaneously, or two half-olives under the same ohel = impure — same-category activities do combine.
8/9
🎓 Key Principles
Chapter 3
📊
Systematic Classification The Rambam organizes all corpse impurity sources into precise groups: 12 convey all three types, 7 convey only touch and carrying, and special cases for golel/dofek/rekev.
🧪
Nazirite as a Gauge of Scriptural Status The Rambam's test: if a nazirite need not shave his hair due to contact with an impurity, it is likely not of Scriptural origin.
⚗️
Natural Decomposition Required Rekev (decomposed matter) must occur naturally inside a proper coffin — artificial grinding or mixed burials do not create valid rekev.
↔️
Categories Don't Combine Touch, carrying, and ohel are mutually exclusive categories — half-measures from different categories never combine to reach the minimum threshold for impurity.