Halakhah zu Wajikra 13:2

The commandment of the matter of the impurity of a metsora: To make a man that is metsora (has a type of skin disease) impure - meaning to say that it is a commandment upon us that anyone who is a metsora come to the priest to ask about his tsaraat, and the priest will render him impure or render him pure; and he will act according to the written Torah, as the priest will command him; and he should not take the thing as an illness that comes by chance, but rather put his [mind] to it and know that the greatness of his iniquity caused it, as it is stated (Leviticus 13:2), "When a man has on the skin of his flesh, etc. it shall be brought to Aharon the priest or to one of his sons, the priests." And this commandment includes all the statutes of tsaraat of a person: that from which one is impure, and that from which one is pure; that from which one requires quarantine and that from which one does not require quarantine; that which requires shaving with the quarantine or does not require shaving - meaning to say shaving of the scab - and many laws besides this.