Kommentar zu Oholot 13:3

החור שבדלת – in the middle of the door, that it is not made for the air.

Introduction Today's mishnah deals with how large an opening in a door must be to allow in and out impurity.

שייר בו החרש – the artisan who prepared/fixed the door.

[With regard to] a hole in the door: Its minimum size is that of a fist, the words of Rabbi Akiva. Rabbi Tarfon says: one handbreadth square. Rabbi Akiva holds that since these holes in the door were not made intentionally, they should be compared with the naturally forming holes referred to in mishnah one. For impurity to travel through such a hole, it must be the size of a fist. Rabbi Tarfon says that it needs only be a handbreadth square (slightly smaller than a fist) for these holes are meant for human use (see mishnah one).

מלמטן – as for example that he left [a hole] near the threshold.

If the carpenter had left a space at the bottom or the top [of the door] or if one had shut [the door] but not closed it tightly, or if the wind blew it open, the minimum size is that of a fist. There are three spaces in a door referred to here: 1) the carpenter didn't make the door as large as it was supposed to be; 2) the door wasn't tightly closed; 3) the wind blew the door slightly open. All of these are openings that were probably not intentionally formed, nor are they holes that are used by human. Therefore, the measure to allow through impurity is that of a fist, which is larger than a handbreadth.

או מלמעלן – near the lintel.

הגיפה (he filled the hole out but not entirely)– he closed it.

ולא מירקה – but didn’t complete it.

או שפתחונו הרוח – meaning to say, or that he competed the closure but the wind came and opened it.

שיעורו מלוא אגרוף – for since it opened on its own, it is like the running water or reptiles. But in this concluding clause [of the Mishnah], Rabbi Tarfon does not disagree because the hole that is in the middle the carpenter made with intention, but not because he needs the hole but rather the boards were short and a door was made from them and he had the intention to place a hole/incision in the middle more than to place it below or above. And it is similar to someone who makes with intention, but when he placed it from below or from above, this is not like doing it with one’s hands, but rather because the boards are short, and the hole wasn’t filled.