ויקרא, פרק י״ג, פסוק ל״ד

At the end of a quarantine period, a person suspected of having a skin affliction on their head or beard undergoes a crucial examination by the priest. On the seventh day, the priest checks to see if the condition has halted its progress. For the individual to remain pure, the affected area must not have spread, and it must not appear deeper than the surrounding skin. However, purity does not actually depend on the visual depth of the mark. A deep affliction is significant only because it causes the growth of yellow hair, which is a clear sign of impurity. Therefore, the requirement that the mark not be deep practically means that it has not produced any yellow hair [ביאור יש״ר, רד צ הופמן]. When evaluating signs of purity, such as the lack of spreading or the growth of black hair, there are different views on the requirements. Some maintain that a single sign is enough to establish purity, while others argue that both signs must be present together [הדר זקנים].

Even if the condition ultimately proves to be ordinary baldness rather than a severe affliction, the priest must explicitly declare the person pure. Unlike someone who loses their hair naturally, this individual is not exempt from a basic purification process [רלב״ג]. The formal declaration of purity allows the person to return to their normal routine. They no longer transfer impurity to the beds or seats they use, and they are completely freed from the complex rituals and mourning customs required of a confirmed afflicted person, such as tearing their garments, letting their hair grow wild, shaving completely, and bringing a bird sacrifice [חזקוני].

To complete the return to purity, the person must wash their clothes. Biblical law recognizes two types of washing: vigorously scrubbing a garment to remove a physical stain, and immersing it in water for spiritual purity. Because there is no physical stain involved in this situation, the requirement is strictly to immerse the clothing [מלבי״ם, אילת השחר]. Furthermore, although the instruction only mentions washing garments, it is understood that the person must also immerse their entire body in water [אבן עזרא, מלבי״ם]. This requirement for bodily immersion and the washing of clothes stems simply from the fact that the individual spent time in quarantine and was considered potentially impure up until the moment of the priest's declaration [רד צ הופמן, רש ר הירש].