From Dan Lifshitz: The primary subject of Parshat Tazria is tzara’at, a supernatural skin disease that, according to the Sages, was a punishment for speaking ill about other people. A person who habitually spoke ill about others would be struck with tzara’at and would then be quarantined outside the city as a divine warning to improve their behavior and make themselves more worthy of dwelling within the community. Although the symptoms of tzara’at were fairly straightforward, the official diagnosis could only be made by a kohen, who would declare whether a given patch of skin contained tzara’at or not. The Torah describes one type of skin lesion called a “bohak” that is not tzara’at, but is required to be shown to a kohen as well. R’ Moshe Feinstein asks about the purpose of this – if it is not tzara’at, why does the Torah trouble people to show it to the kohen?
R’ Moshe Feinstein explains based on the insight mentioned earlier. The purpose of tzara’at is to cause a person to evaluate their behavior and to make improvements. The trauma of being quarantined outside the city for a week or more is clearly a strong catalyst for such self-examination, similar to the way serious illness or loss of a job triggers self-examination in our day. But we must not wait for such dramatic events to examine our actions. The law of the bohak teaches us that even smaller events in our lives should be seen as catalysts for introspection and self-improvement. We can never know for certain what messages G-d is trying to send us, but we should always be listening, whether the message is loud or not.