פירוש על ויקרא 13:28

לא פשתה בעור והיא כהה, “it has not spread on the surface of the skin and has dimmed;” this means that if it has spread although its appearance did not change, it will be declared as making its victim ritually impure.

לא פשתה בעור והיא כהה, “it had not spread on the skin, and had become dimmer in appearance;” the word כהה is used as complementing the words לא פשתה, i.e. “it had not spread and not become dimmer.” (Compare our commentary on verse 21 in connection with שחין)