Houses are inspected as follows: “The one who owns the house shall come and tell the kohein, ‘Something that seems like a nega has appeared on my house’” (Leviticus 14:35). Even if he is a learned scholar and knows for sure that this is a nega, he may not declare definitively that a nega has appeared on his house; he must say that something that seems like a nega has appeared. “The kohein shall order the house emptied before he enters to examine the nega so that nothing in the house should be rendered unclean. Then the kohein shall enter to examine the house” (ibid., verse 36). Rabbi Yehuda says that even bundles of wood and reeds (which are normally insusceptible to ritual impurity) are removed; Rabbi Shimon says they are removed to be part of emptying the house. Rabbi Meir asks which items might be rendered unclean; if you say his wooden utensils, garments and metals, these could be immersed and purified. Rather the Torah is taking pity on his earthenware, his cruse and his flask. If the Torah takes pity on a person’s most insignificant possessions, how much more it is concerned for one’s valuables! If the Torah takes pity on a person’s material possessions, how much more it is concerned for the life of one’s sons and daughters! If the Torah takes pity on an evil person’s possessions, how much more it is concerned for a righteous person’s possessions!
The kohein may not go into his own house to declare a quarantine, nor may he stand in the house that has the nega. Rather, he must stand at the door to the infected house and quarantine it from there, as per Leviticus 14:38, “The kohein shall come out of the house to the door of the house and close the house for seven days.” He comes at the end of the week and inspects; if the nega has spread, then “the kohein shall order the infected stones to be removed and thrown outside the city into an unclean place… They shall take other stones and put them in the place of those stones, and take other mortar and plaster the house" (ibid., verses 40, 42). He may not take stones from one side and bring them to the other, nor may he take mortar from one side to the other, nor may he bring lime from anywhere. He may not bring one stone to replace two, nor two to replace one but he can bring two to replace two, three or four. Based on this they said, “Woe to the wicked and woe to his neighbor.” This is because both owners of adjoining houses must remove the infected stones, scrape the walls and bring new stones. Only the owner of the infected house must brings the mortar as per Leviticus 14:42, “he shall take other mortar and plaster the house,” i.e., his neighbor does not join him in plastering.