Study Eruvin folio 6B with parallel Hebrew-English text, traditional commentary, and modern study tools. Free access to Babylonian Talmud online.
Text Excerpt
מי שהיו לו שני בתים משני צידי רשות הרבים, עושה לחי מכאן ולחי מכאן, או קורה מכאן וקורה מכאן, ונושא ונותן באמצע. אמרו לו: אין מערבין רשות הרבים בכך.
One who has two houses opposite each other on the two sides of the public domain, and he wishes to carry from one house to the other on Shabbat via the public domain, he may place a side post from here, on one side of one of the houses, and an additional side post from here, on the other side. Alternatively, he may place a cross beam from here, from one end of one house, and an additional cross beam from here, from the other side of the house, and then he may carry objects and place them in the area between them, for in this manner he turns the middle area into a private domain. The Rabbis said to him: One cannot render a public domain fit for carrying by means of an eiruv in this manner. Apparently, there is no way to establish an absolute public domain fit for carrying by means of an eiruv.
וכי תימא בכך הוא דלא מיערבא, הא בדלתות מיערבא, והאמר רבה בר בר חנה אמר רבי יוחנן: ירושלים, אילמלא דלתותיה ננעלות בלילה — חייבין עליה משום רשות הרבים!
The Talmud questions its previous conclusion: And if you say that it is only in this manner, by way of a side post or a cross beam, that a public domain cannot be rendered fit for carrying, but by means of doors it can be rendered fit for carrying. But this is not true, as didn’t Rabba bar bar Ḥana say that R' Yoḥanan said: With regard to Jerusalem, were it not for the fact that its doors are locked at night, one would be liable for carrying in it on Shabbat, because its thoroughfares are regarded as a public domain? This shows that the presence of a door is not sufficient to render it permitted to carry in a public domain; rather, the door must actually be locked.