Ohalos 3:7-4:1

Ohalos 3:7

Something one handbreadth by one handbreadth and one handbreadth high both conveys and blocks ritual impurity. For example, if an arched drain under a house has an opening one handbreadth wide and its outlet was a handbreadth wide, if there’s something ritually unclean in the drain, the house remains pure. Similarly, if there’s something ritually unclean in the house, things in the drain remain pure because the nature of ritual impurity is to go out, not in. If the drain had an opening one handbreadth wide but its outlet wasn’t one handbreadth wide, then if there’s something ritually unclean in it, the house is rendered unclean but if there’s something ritually unclean in the house, things in the drain remain clean because the nature of ritual impurity is to go out, not in. If the drain didn’t have an opening one handbreadth wide and its outlet wasn’t one handbreadth wide, then if there’s something ritually unclean in it, the house is rendered unclean, and if there’s something ritually unclean in the house, then what’s in the drain is rendered unclean. It makes no difference if a cavity was formed by water, vermin or salt. The same is true of a row of stones or a pile of beams (i.e., it makes no difference how they were formed). Rabbi Yehuda says that any tent not made by a person is no tent at all but he agrees that crevices and caves are considered tents.

Ohalos 4:1

Let’s say that a cupboard was standing in the open air. If there’s something ritually unclean in it, utensils in the thickness of its walls remain clean. If there’s something ritually unclean in the thickness of its walls, utensils in its interior remain clean. Rabbi Yosi says half and half (i.e., half the thickness of the wall is considered like the inside and half like the outside). When the cupboard is standing inside a house, if there’s something ritually unclean inside it, the house is rendered unclean but if there’s something ritually unclean in the house, then the contents of the cupboard remain clean because the nature of ritual impurity is to go out, not in. Regarding utensils that are between the cupboard and the ground, the wall or the rafters, if there’s an opening of one handbreadth there, they are rendered unclean and if not, they remain clean. If there’s something ritually unclean there, the house is rendered unclean.