Parashas Metzora · Passuk 14:35
Chabad.org — English translation + Rashi
Torah Temima points to Toras Kohanim.
English: “In the house” — it conveys tumah from its interior, but it does not convey tumah from its exterior.
Interior vs. exterior
Chazal teach that the impurity of a house-nega affects only what is inside the house, not what is outside its walls.