Leviticus 13:6

3 The priest is to examine the infection on his skin, and if the hair in the infection has turned white and the sore appears to be deeper than the skin, it is a skin disease. After the priest examines him, he must pronounce him unclean.

4 If, however, the spot on his skin is white and does not appear to be deeper than the skin, and the hair in it has not turned white, the priest shall isolate the infected person for seven days.

5 On the seventh day the priest is to reexamine him, and if he sees that the infection is unchanged and has not spread on the skin, the priest must isolate him for another seven days.

6 The priest will examine him again on the seventh day, and if the sore has faded and has not spread on the skin, the priest shall pronounce him clean; it is a rash. The person must wash his clothes and be clean.

7 But if the rash spreads further on his skin after he has shown himself to the priest for his cleansing, he must present himself again to the priest.

8 The priest will reexamine him, and if the rash has spread on the skin, the priest must pronounce him unclean; he has a skin disease.

9 When anyone develops a skin disease, he must be brought to the priest.