Leviticus 13:1-8

And Jehovah spake unto Moses and unto Aaron, saying, When a man shall have in the skin of his flesh a rising, or a scab, or a bright spot, and it become in the skin of his flesh the plague of leprosy, then he shall be brought unto Aaron the priest, or unto one of his sons the priests: and the priest shall look on the plague in the skin of the flesh: and if the hair in the plague be turned white, and the appearance of the plague be deeper than the skin of his flesh, it is the plague of leprosy; and the priest shall look on him, and pronounce him unclean. And if the bright spot be white in the skin of his flesh, and the appearance thereof be not deeper than the skin, and the hair thereof be not turned white, then the priest shall shut up him that hath the plague seven days: and the priest shall look on him the seventh day: and, behold, if in his eyes the plague be at a stay, and the plague be not spread in the skin, then the priest shall shut him up seven days more: and the priest shall look on him again the seventh day; and, behold, if the plague be dim, and the plague be not spread in the skin, then the priest shall pronounce him clean: it is a scab: and he shall wash his clothes, and be clean. But if the scab spread abroad in the skin, after that he hath showed himself to the priest for his cleansing, he shall show himself to the priest again: and the priest shall look; and, behold, if the scab be spread in the skin, then the priest shall pronounce him unclean: it is leprosy.