The mitzvah regarding the ritual impurity of the metzora (a person suffering from tzaraat, a skin discoloration described in the Torah). This mitzvah includes all the laws applicable to this impurity: what types [of discolorations render a person] impure, and what types [do not]; which types of this impurity require quarantine, and which do not; the laws associated with the quarantine, i.e., shaving [the hair surrounding a tzaraat lesion in an area of hair]; and all other laws associate with tzaraat and the gradations of its impurity.