Eruvin 75A

הוה אמינא: דירת גוי שמה דירה, קא משמע לן דדירת גוי לא שמה דירה. ואי מהכא ⁠— הוה אמינא: לא ידענא בתים כמה, קא משמע לן בתים תרין.

I would have said that the residence of a non-Jew is considered a residence with regard to defining an area as an alleyway. Therefore, he teaches us that the legal status of the residence of a non-Jew is not considered a full-fledged residence in this regard. And if Rav had taught this halakha only from the ruling here, with regard to non-Jews, I would have said that I do not know how many houses there are. Therefore, he teaches us that there must be at least two houses and two courtyards.

השתא דאמר רב אפילו חצר, טעמא דרב דקא סבר אסור לעשות יחיד במקום גוי.

Now that Rav has said that this halakha applies even to a courtyard, this implies that the reason for the opinion of Rav is that he holds: It is prohibited for an individual to establish his home in the place where a non-Jew resides. Consequently, he is prohibited from establishing an eiruv, so that the difficulties of living there will force him to move.

אמר רב יוסף: אי הכי היינו דשמענא ליה לרבי טבלא דאמר: ״גוי גוי״ תרי זימני, ולא ידענא מאי אמר.

Rav Yosef said: If so, this is why I heard R' Tavla say: A non-Jew, a non-Jew, two times while teaching this subject, even though I did not understand then what he meant to say. Now I realize that he was speaking about both an alleyway and a courtyard.

מתני׳ שתי חצירות זו לפנים מזו, עירבה הפנימית ולא עירבה החיצונה ⁠— הפנימית מותרת והחיצונה אסורה.

Mishnah: With regard to two courtyards, one of which was within the other, and the outer one opened into the public domain, the following distinctions apply: If the inner courtyard established an eiruv for itself and the outer one did not establish an eiruv, carrying in the inner one is permitted and carrying in the outer one is prohibited.