Leviticus 13:29-33

29And if a man or a woman have a sore on the head or on the beard,

30and the priest look on the sore, and behold, it looketh deeper than the skin, and there is in it yellow thin hair, then the priest shall pronounce him unclean; it is a scall, the leprosy of the head or the beard.

31And if the priest look on the sore of the scall, and behold, it is not in sight deeper than the skin, and there is no black hair in it, the priest shall shut up [him that hath] the sore of the scall seven days.

32And when the priest looketh on the sore on the seventh day, and behold, the scall hath not spread, and there is in it no yellow hair, and the scall doth not look deeper than the skin,

33he [that hath the sore] shall shave himself; but the scall shall he not shave; and the priest shall shut up [him that hath] the scall seven days a second time.