ויקרא, פרק י״ג, פסוק י׳

When a person is brought to the priest for diagnosis, the examination focuses on specific biological changes that reveal a deep physical and spiritual illness. The appearance of a distinct skin affliction, accompanied by secondary symptoms, seals the diagnosis of ritual impurity. The priest specifically looks for sudden developments or new changes in the skin's appearance since it was first noticed or previously examined [תורה תמימה, מלבי״ם, אדרת אליהו]. The primary indicator is a white discoloration that appears distinctly raised and prominent above the surrounding skin, contrasting with other afflictions that appear sunken [שטיינזלץ, בכור שור, העמק דבר].

To confirm ritual impurity, this raised spot must be accompanied by secondary symptoms. The first potential symptom is the transformation of hair within the spot to white. Since natural human hair is dark, this whitening signals a profound disease and an alteration of nature [רבנו בחיי, אבן עזרא]. It is crucial that the current raised spot directly caused the hair to change color, rather than an older, pre-existing condition [תורה תמימה, מלבי״ם, הופמן]. For this symptom to take effect, at least two hairs must turn white [רבנו בחיי, תורה תמימה, מלבי״ם], and the color is always determined by examining the root of the hair [רבנו בחיי].

The second potential symptom of impurity is the appearance of raw flesh within the raised spot. Most commentators understand this as the growth of red, healthy tissue that retains physical sensation inside the white affliction [רש״י, אבן עזרא, שטיינזלץ, הופמן, ביאור יש״ר], while a differing view suggests it refers to diseased, spongy flesh [שד״ל]. Regardless of the exact nature of the tissue, the presence of this flesh acts as a sign of impurity across all major categories of skin afflictions, not just the raised variety [רש״י, מזרחי, ברטנורא, גור אריה].

Although these two symptoms are presented together, they do not need to occur simultaneously. The presence of either white hair alone or raw flesh alone is entirely sufficient to render the person impure [רמב״ן, טור הארוך, שפתי חכמים, רלב״ג]. If each symptom stands alone, their conceptual pairing serves a distinct diagnostic purpose. The primary approach among commentators is that linking them establishes the minimum required size for an affliction to be deemed impure. The affected area must theoretically be large enough to contain both the space for two white hairs and an equivalent area of raw flesh. Based on this, the minimum size is calculated as the area of a split bean, equivalent to a square space containing thirty-six hairs [אור החיים, רלב״ג, מלבי״ם, רש״ר הירש, הופמן].

Furthermore, the raw flesh must be entirely enclosed within the raised white spot, surrounded like a fortress within a wall. This specific placement is critical for the diagnosis. Natural healing typically progresses from the outer edges of a wound inward. Therefore, if healthy-looking flesh appears in the center while the edges remain afflicted, it is not a sign of recovery. Instead, it proves that the decay originates from deep within the body and is actively pushing outward to the skin, confirming the impurity [תורה תמימה, רלב״ג, פרדס יוסף]. Finally, this patch of flesh must be located strictly within the primary raised affliction, rather than inside a secondary condition such as a boil or a burn [מלבי״ם].