The white hair that is a sign of impurity for tzara'at is not less than two hairs. How long must they be? Long enough to be pulled out by tweezers. If one was long and the other was shorter than this measure or one was black and one white, or one was whole below but split in two above and so it appeared as two, or its base was black, but its top was white, the person is pure. If its base was white and its top dark, even though only the slightest amount was white, he is impure.
When there are two white hairs in a blemish, even though there is black hair between them and they are scattered, one in this portion and one in another portion, they serve as a sign of impurity. Even if the blemish was exactly the size of a gris, the space of the black hair does not reduce its size. Whether the two hairs are in the midst of the baheret and it surrounds them or they are at its edge, the person is impure. If, however, they are at its side, outside of it, he is pure. The skin from which the two white hairs grow must be white in order to impart impurity. If the two hairs originate in the midst of the blemish, but lie out of it, he is impure. If they originate outside of it, but lie within it, they are not a sign of impurity.
Any shade of whiteness in the hair causes the person to be deemed impure, whether they were white as snow or a very weak shade of whiteness. Since they appear white, he is impure.
🔬 White Hair Basics
To constitute a sign of impurity, two white hairs are required, long enough to be pulled by tweezers. They must both be truly white (any shade of white qualifies), and their roots — not just the tips — must be white. A single white hair, a split hair appearing as two, or hairs with dark roots do not qualify.
White hair is not a sign of impurity unless it is inside the baheret itself. What is implied? If there is a baheret and in its midst there is a boil, burnt skin, a bohak, a boil that has healed, a burn that has healed and there were two white hairs in the boil, the burnt flesh, or the bohak that is in the midst of the blemish, they are not signs of impurity. It is like a baheret that does not have white hair, in which instance, the person should be isolated. This ruling is rendered even though the baheret surrounds the boil, the burnt flesh, the healed boil or burnt flesh or the bohak in which the two hairs were located. Similarly, if the boil, the burnt flesh, the healed boil or burnt flesh or the bohak surround the two hairs, they are not a sign of impurity. The baheret is like a baheret that does not have white hair and the person should be isolated.
If the boil, the bohak, or the burnt flesh that surround, are next to, or divide the white hairs disappear and thus the two hairs are found in the baheret itself at the end of the first week or the end of the second week of the isolation period, the person is declared as definitively impure. If these abnormal skin features do not disappear, he should be released from the process of inspection.
📍 Location Matters
White hair is a sign of impurity only when it is inside the baheret itself. If the hairs are within a boil, burn, or bohak that is within the blemish, they do not count. However, if these intervening conditions disappear during the isolation period, leaving the hairs inside the baheret alone, the person is declared definitively impure.
White hair is not a sign of impurity unless the baheret precedes the white hair. This can be inferred from Leviticus 13:10: "And it turned hair to white." Implied is that the baheret caused it to turn white. If, however, the white hair existed before the baheret, it is like a baheret that does not have a sign and the person should be isolated.
The following rule applies when a person had a baheret which contained white hair which caused him to be deemed definitively impure, and afterwards, the baheret disappeared and left the white hair in its place. He was then deemed pure. Afterwards, another baheret returned to the place of the first baheret and thus there was white hair in its midst. This hair is called "entrusted hair." It is not a sign of impurity. The phrase "And it turned hair to white" implies that the baheret in question must cause the color of the hair to change and not another baheret.
The following rules apply if a person had a baheret the size of a gris, it contained two white hairs, and therefore he was deemed definitively impure. A portion half the size of a gris disappeared and he was deemed pure. The two hairs were located in the portion half the size of a gris that remained. Afterwards, half a gris returned to the place where the half that disappeared was. Thus there were two white hairs in a baheret the size of a gris. This is not considered a sign of impurity, for one entire baheret must cause the color of the two hairs to change.
⏱️ Temporal Order
White hair is only a sign of impurity if the baheret preceded the hair — the blemish must have turned the hair white. If white hair existed before the blemish appeared, the person is isolated rather than declared impure. Similarly, 'entrusted hair' (left from a previous baheret now replaced by a new one) is not a valid sign.
When a person had a baheret that was half the size of a gris without any white hair inside of it and then another baheret that was half the size of a gris which contained one white hair erupted at its side, the person should be isolated. If a person had a baheret that was half the size of a gris with one white hair inside of it and then another baheret that was half the size of a gris which contained one white hair erupted at its side, the person should be isolated. When a person had a baheret that was half the size of a gris which contained two white hairs and then another baheret that was half the size of a gris which contained one white hair erupted at its side, this person should be isolated. When a person had a baheret that was half the size of a gris without any white hair inside of it and then another baheret that was half the size of a gris which contained two white hairs erupted at its side, the person should be deemed definitively impure. The rationale is that a baheret preceded the two white hairs. When there is a doubt whether the white hair came first or the baheret came first, the person is deemed impure. It appears to me that this impurity is of a questionable nature.
❓ Combined Cases
When two half-gris blemishes combine to form a full gris, the distribution of hairs between them matters greatly. A new blemish half with two white hairs arising after an empty half qualifies for declaration of muchlat, since the blemish preceded the hairs. In cases of genuine doubt about which came first, the person is deemed impure (though possibly with uncertain impurity).
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🎓 Key Principles
Chapter 2
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Two Hairs, Not One A single white hair is never sufficient — the minimum sign requires two white hairs, each long enough to be grasped by tweezers.
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Roots Determine Validity It is the root (base) of the hair, not the tip, that must be white — a white-tipped hair with a dark root is pure, but a dark-tipped hair with a white root is impure.
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Sequence Is Decisive The law turns on temporal sequence: the baheret must cause the hair to turn white, not the reverse. Pre-existing white hair within a newly appeared blemish does not create impurity without isolation.
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Continuous Identity Required A single baheret must turn both white hairs — the requirement cannot be fulfilled by two different blemishes each turning one hair, nor by replacement blemishes acting on previously-turned hairs.