A metzorah is a source of tumah. We have learnt that a metzorah can make other objects tameh if they are under the same covering, even if not in direct contact. There are however differences regarding the nature of the covering - whether we are dealing with a house or tree.
The Mishnah (13:7) taught if a metzorah is standing under a tree, even if someone else simply walks under the tree they would become tameh. If, however, the metzorah walked under the tree without stopping, then anything else under the tree would remain tahor.
The Bartunura explains that the reason is because, when the Torah teaches that a metzorah is tameh it states, "his dwelling (moshavo) shall be outside the camp" (Vayikra 13:46). He continues, only when the metzorah is standing, can his location be considered moshavo.
The Mishnah Achrona continues, that if a metzora enters a house, he would also make it tameh, based on the pasuk "Anyone who comes into the house... it shall be contaminated until evening" (Vayikra 14:45).
The Mishnah Achrona continues that in our Mishnah it appears that the metzorah would only be a source of tumah under the tree if his entire body were under the tree. In contrast, we learn in the next Mishnah, that even if a metzorah's head and most of his body extended into the house, would it be tameh. The Tosfot Yom Tov (13:8) cites the Tosfot who explain that a house is different since it has walls. Consequently, once most of the body is inside, it is considered as if the entire body is situated there.
The Mishnah Achrona is unsure why the walls make a difference. He suggests that perhaps it is because the walls mark the boundary of the house and once one places a majority of their body on the other side, it expresses one's intent on being there. For a tree however, one's intent is not expressed unless that are full located there. He continues, that this explanation would fit with the explanation of the Bartenura. The Mishnah teaches that if a metzora passes under a tree and stop momentarily, everything under the tree is tameh. The Bartenura explains that that is only if he stops to readjust his load -- an intentional stopping. The other Rishonim however do not explain the Mishnah in this way. Intent therefore does not seem to be critical.
The Mishnah Achrona however continues, that were it not for the Tosfot's comment he would have explained that the difference is based on the above pesukim. The term "alone shall he dwell (yeshev)" implies "ikuv" - a delay or being stationary. For a place to be termed as moshovo, the entire body is required. With respect to the tumah in a house, the Torah did not mention "yeshev" but only entering (bi'ah) -- and for that his head and a majority of his body is sufficient.
The truth is, there is a Rishon that explains the difference between the tree and house in this manner, albeit to resolve another difference. We have seen that the metzorah is only source of a tumah under the tree if he stands. If a metzorah enters a house however, we do not find this requirement. Even if the metzorah is continually walking, the contents of the house would be tameh. The Ritva (Kidushin 33b) cites the distinction of the Tosfot, yet explains it based on the same logic presented by the Mishnah Achrona. In other words, without walls, ikuv is required for it to be defined as moshavo. For a house however, ikuv is not required since only bi'ah is mentioned as a cause for the house to be tameh. Consequently, even if the metzorah walks straight through the house, it would become tameh.
Receive our publication with an in depth article and revision questions.
Listen to the Mishnah Shiurim by Yisrael Bankier