Ohalot, Chapter Ten, Mishnah Seven
1) [In the case where the pot was] placed on the side of the threshold [of the house] such that if it was raised it would touch the lintel over a [space of a square] handbreadth:
2) If there is uncleanness below, within or above [the pot], the uncleanness cleaves upwards and downwards.
3) [In the case] where it was one handbreadth high off the ground:
4) If there is uncleanness below it or in the house, what is below it and in the house becomes unclean.
5) If the uncleanness is within or above [the pot], everything becomes unclean.
6) [In the case where the pot] if raised would not touch the lintel over a [space of a square] handbreadth, or is joined to the lintel, if there is uncleanness below it, nothing is unclean except what is below [the pot].
Section one: Today’s mishnah deals with a pot that is placed on its side outside of a house, on the threshold of the house. The pot is placed such that if it was lifted up, at least one handbreadth square of the pot would touch the lintel.
Section two: In this case, no matter where the impurity is, it goes only up and down. If it is below the pot, then it is not in an ohel that is one cubic handbreadth in size. If it is in the pot or on its side, then the house remains pure because the impurity is not within the lintel (which would place it in the house).
Section three: As the mishnah always seems to do, it now discusses what happens if the pot is a one handbreadth off the ground.
Section four: In this case there is an ohel (under the pot) that is immediately connected to the house (because there is no space between it and the house). The wall of the pot, if lifted, would connect at the length of a handbreadth with the lintel of the house. Therefore, if the impurity is either under the pot or in the house, it spreads from one to the other and both are unclean.
Section five: If the uncleanness is within or above the pot, then the pot is defiled and it doesn’t form a barrier to protect the house (see mishnah six).
Section six: In this case, the pot is again one handbreadth off the ground. In this case, if it were lifted, it would not touch a space of one square handbreadth of the lintel. Alternatively, the pot is raised all the way to the lintel, but it comes into contact with less than one handbreadth of the lintel. In these cases, if impurity is below it, it remains there. The pot does form an ohel over the impurity and therefore the entire area below the pot is impure. However, the house is pure since the pot touches the lintel for a space less than one handbreadth. In order for two ohels to be connected to convey impurity the contact must be at least a handbreadth. The inside of the pot and above the pot are pure for the pot joins with the walls of the house to serve as a barrier, even though it is connected at a point of less than a handbreadth.