“If a human being has on the skin of his flesh a swelling or a scab or a bright spot, and it becomes an infection of leprosy, he shall be brought to Aaron the priest.”
The interpreters asked why it is written “a human being” and not “a man,” perhaps as was said, “You are called ‘man’” (Yevamot 61). This is a proof that the idol-worshippers do not defile with afflictions.
They said, “If a human being has on the skin of his flesh,” meaning that the Tuma’a [impurity] of leprosy is not on the Israeli man, but on the skin of his flesh and not inside, for in idol-worshippers, their very selves and soul was leprosy and its kind. But when they afflict the Israeli soul, it is next to the sin that he will sin, and as the appearance of leprosy in the skin of his flesh and specifically on his skin and not in his flesh, much less in his interior (Light of Life).
We should ask, 1) Why specifically “You are called ‘man.’” 2) Why next to his being called “man,” in his interior, he is pure.
We should explain according to what our sages said about the verse, “In the end, all is heard, fear God and observe His commandments for this is the whole of man.” He said, “What is ‘for this is the whole of man’?” The whole world was created only for this man; he is equal to the whole world; the whole world was created only to command this (Berachot 6).
This means that the meaning of “man” is fear of heaven. Hence, “You are called ‘man’” refers to fear of heaven, for one who has fear of heaven is called “man.” It therefore follows that sometimes he commits a sin by chance, which is called “his externality,” implied by the skin, for skin is externality, as is explained that there are discernments of Mocha [marrow], Atzamot [bones], Gidin [tendons], Bassar [flesh], and Or [skin].
It is explained that one who is called Adam [man] is internally pure and the Tuma’a that sometimes appears in him through a sin is only on the outside. Hence, idol-worshippers, namely those who have no fear of heaven, are without leprosy; they are impure from within.
“Sin” pertains only to one who has fear of heaven, who is called “man.” The sin manifests in him in the form of leprosy, attached to the person.
But one who has no fear of heaven is full of sins and his interior is also inappropriate. Hence, a sin cannot be regarded as his exterior; rather, he is impure also within.
And to achieve fear of heaven is through the Torah, as our sages said, “The light in it reforms him.”