פירוש על עירובין 5:2

נותנים קרפף לעיר (for measuring the Sabbath limits, we allow an area of seventy-square cubits outside the town added to the town – for the purpose of the Sabbath limits) – all who come to measure the [Sabbath] limits leaves to the city/town the air-space of seventy cubits and left-overs, which are seventy cubits and two-thirds of a cubit, and from there, he begins to measure two-thousand cubits, as it states (Numbers 35:4): “[The town pasture that you are to assign to the Levites] shall extend a thousand cubits outside the town wall all around,” the Torah stated that one should give outside [the wall] and afterwards measure, meaning to say, give it an area of seventy-square cubits and remnants outside the town added to the town and afterwards measure from there and beyond/further.

Introduction A karpaf is a field used for storing wood. Its typical size is seventy cubits and a fraction long. In our mishnah the sages debate whether the size of a town is automatically extended by a karpaf.

לא אמרו קרפף אלא בין שתי עיירות – two towns that are adjacent/near each other, they given seventy cubits and left-overs to each one in order to attach/combine them through these enclosures to become like one city, and a person who comes to walk from one of them [through] its neighbor measures for himself two-thousand cubits from outside its neighbor, because since both of them are like one town/city through these enclosures that connect between them. And the Halakha is according to the Sages, for we don’t place an enclosure for one town/city, but rather only between two towns/cities.

They give a karpaf [as an extension] for every town, the words of Rabbi Meir. According to Rabbi Meir, when measuring the Shabbat limit they extend a karpaf’s length of a field to the size of the city. From the end of this field they will measure the 2000 cubits square.

But the sages say: they said [the of a] karpaf only in regard to two towns that if there was to this one [a piece] of land of seventy cubits and a fraction and to the other one [a piece of land] seventy cubits and a fraction, they can consider the karpaf as combining the two into one. The other sages do not agree that every city is automatically extended by a karpaf. They agree that there was a halakhah stated concerning a karpaf and its use in extending a city, but this halakhah is more limited in scope. If there are two cities close enough to one another that if there was a karpaf of seventy and a fraction cubits attached to each one, they would overlap (they are not more than 140 and 2/3 cubits apart), then the two cities can be considered one. The ramification would be that people could go from one to the other and that their Shabbat border would be drawn around the two cities.