Although we have been discussing the limitation of travel beyond 2,000 amot throughout Massekhet Eiruvin, that applies only outside the city limits. If one resides in a large city, the entire city is considered to have the status of daled amot – four cubits – and one can walk wherever he wants in it. This is also true if two cities are within 2,000 amot of one another. In such a case, were one to place his eiruv in the neighboring city, he would be permitted to walk anywhere in that city – even if it is well beyond the normal 2,000 ama limit. The Mishna also brings the opinion of Rabbi Akiva, who argues that movement within the larger city for people who are coming from a neighboring city would be limited to 2,000 amot from their eiruv, even within the precincts of the city.
Rabbi Akiva’s opinion is not accepted as the halakha. To illustrate this, the Gemara tells of people who were arranging their eiruv in a neighboring city so that they would be able to travel there on Shabbat.
The Gemara relates that Mar Yehuda once found the residents of Mavrakhta placing their eiruvin in the synagogue of Beit Agovar. He said to them: Place your eiruv farther into the synagogue, so that more will be permitted to you, as the limit is measured from the spot where the eiruv is deposited. Mar Yehuda holds that even when an eiruv is placed in an inhabited city, the two thousand cubits are measured from the location of the eiruv rather than from the edge of the city.
Rava said to him: Argumentative one [palga’ah]! With regard to the of eiruv, nobody is concerned about this opinion of Rabbi Akiva, as the is in accordance with the opinion of the Rabbis. Consequently, no matter where one places his eiruv in a city, the entire city is considered as though it were four cubits, and he is permitted to walk two thousand cubits beyond the edge of the city.
The Aruk defines palga’ah as someone always looking for a fight who took up positions that were not generally accepted. Rashi explains the term to mean that he was known to argue with the Sages, who, in this case, had already ruled that the halakha follows the lenient position.
The example of a large city that appears in the Gemara is Antioch, about which the baraita teaches that someone who establishes his Shabbat there can walk its full length and breadth, its size notwithstanding.
Antioch in Northern Syria was one of the largest cities in the world during the ancient period. Since it was built over a period of time – and, at its peak, was actually composed of four separate, joined cities – it was not well planned, part of the reason that it covered such a large area. During the Talmudic period, about 600,000 people lived there.