Commentaire sur Oholot 9:2

היתה גבוהה מן הארץ טפח – that now there is a tent of a handbreadth underneath it.

[In the case of the hive] being one handbreadth high off the ground, If the hive is one handbreadth high off the ground, then it will form an ohel over a piece of impurity that is found below it. This will cause the impurity to spread to the sides.

הכל טמא – that it brings the defilement into the house since it is a handbreadth high, and vessels that are on top of it, even those that are not opposite the defilement are also impure and even outside, for underneath it is like one that is full of defilement. And it doesn’t protect what on top of it, for the vessel does not protect. And similarly, if the defilement is also in the house everything is ritually impure from this reason, for the tent of the house brings the defilement to what is underneath it and doesn’t protect that which is on top of it. But if the defilement is on top of it, since it doesn’t protect over what is underneath it, we view what is beneath it as one that is filled with defilement, therefore, whatever is in the house and what is underneath it and what is on top of it -everything is impure.

If there is uncleanness below it or in the house or above it, everything becomes unclean except that which is within [the hive]. Thus if there is uncleanness underneath the hive, it will defile everything else underneath it and anything above it. Similarly, if there is impurity above the tent, the impurity will spread below for there is no barrier, and from there it will spread to the sides. It will even enter the house, as there is nothing sealing the house off. The only thing that will remain clean is the inside of the hive, as was the case in yesterday's mishnah.

אלא תוכה -that is to say, everything is impure except for what is within it (i.e., the house) which is pure.

[If the uncleanness is] within the hive everything becomes unclean. If there is a space of one handbreadth underneath the hive and there is impurity in the hive, everything is unclean, which is the same halakhah as in yesterday's mishnah.