One who intended to establish his Shabbat abode in the public domain at a specific site must place food sufficient for two meals for that site to be considered his legal residence. And if he placed the food used for his eiruv in a pit above ten handbreadths, i.e., less than ten handbreadths below ground level, his eiruv is an eiruv. If he placed the eiruv below ten handbreadths from ground level, his eiruv is not an eiruv. Because the pit is a private domain and he may not carry the eiruv from that private domain to a public domain, where he has established his residence, the eiruv is invalid.

The Gemara seeks to clarify the details of this case. What are the exact circumstances? If you say that the baraita is referring to a pit that has ten handbreadths in depth and the phrase: And he placed it above ten handbreadths, means that he raised the eiruv and placed it within ten handbreadths of ground level, and the phrase: Below ten handbreadths, means that he lowered the eiruv and placed it ten handbreadths or more below ground level, what difference does it make to me if the eiruv is above ten handbreadths and what difference does it make to me if it is below ten handbreadths? In any case, the pit is a private domain, and the principle states that the private domain extends from its lowest point to the sky. There is no difference whether the eiruv was placed higher or lower. In any case, he is in one place, in the public domain, and his eiruv is in another place, in the private domain. Since he cannot take the eiruv out of the pit, his eiruv is not an eiruv.

Rather, is the baraita not referring to a pit that does not have in it a depth of ten handbreadths? And the baraita should be understood as follows: If he placed his eiruv below ten handbreadths, refers to a pit whose lowest point is ten handbreadths or more below ground level. If he placed his eiruv above ten handbreadths, refers to a pit that is less than ten handbreadths deep and is not a private domain. And, with regard to that case, it was taught that his eiruv is an eiruv. Consequently, usage under duress in a pit that is less than ten handbreadths deep is considered usage, and a pit of that kind is a full-fledged part of the public domain.

Rava suggested various responses to this objection. At times he would answer him that it is referring to a case where both he and his eiruv are in a karmelit, i.e., that he intended to establish residence in a karmelit and placed his eiruv there. The pit is less than ten handbreadths deep, and consequently, both he and his eiruv are in the same domain. And why does the baraita call his place of residence the public domain? Because it is not the private domain.

And at times he would answer him that it is referring to a case where he was, indeed, in the public domain and his eiruv was in a karmelit, as a pit that is not ten handbreadths deep is not part of the public domain, rather it is a karmelit. With regard to the question, how can this be considered a legitimate eiruv as it is forbidden to carry from a karmelit to a public domain as well, this baraita is in accordance with the opinion of Rabbi Yehuda HaNasi, who said: Anything that is prohibited on Shabbat and its prohibition is not by Torah law, rather it is due to a rabbinic decree [shevut], the Sages did not issue the decree to apply during twilight, which is neither definitive day nor definitive night. Consequently, at the time that the eiruv was placed in the karmelit it was permissible for him to carry it to the public domain. Since an eiruv takes effect even if it is fit for use just one moment during twilight on Shabbat eve, his eiruv is effective.

And Rava said to Rav Adda bar Mattana: Do not say that I am just putting you off with these answers. Rather, what I am saying to you is accurate. The opinion that usage under duress is not considered usage is a bona fide opinion and the suggested answers are appropriate explanations of that baraita. As we learned in a mishna: If there was a swamp and the public domain passes through it, one who throws an object into it at a distance of four cubits is liable just like anyone who carried four cubits in the public domain. And how deep is this swamp? It is less than ten handbreadths. The mishna adds: And with regard to a swamp that the public domain passes through it, one who throws four cubits into the swamp is liable.

The difficulty concerning the repetition of the same topic with virtually identical words is clear, and therefore: Granted, it is possible to explain, that swamp swamp was repeated twice; one case is referring to the summer, and one case is referring to the rainy season. And it is necessary to emphasize that this ruling is in effect both in the summer and in the winter. As, had the mishna told us this halakha only in the summer, we would have said that since people commonly pass through the swamp to cool themselves, it is considered part of the public domain. However, in the rainy season I would have said it is not part of the public domain. And conversely, had the mishna told us this halakha only in the rainy season, I would have said that since he is filthy anyway, it happens that he is not cautious and enters into the swamp. However, in the summer, when he is not dirty with mud, I would have said that it is not part of the public domain. Therefore, it was necessary for the mishna to repeat swamp twice, to teach us that this halakha applies at all times.

However, why do I need the mishna to state twice that the public domain passes through that swamp? Rather, shouldn’t one conclude from this that passage, even when it is under duress, and not free and easy, is considered passage, but usage under duress is not considered usage? It was necessary to emphasize that the public domain actually passes through it. If the multitudes do not pass through it and it was only used under duress, it would not have been considered a public domain. The Gemara concludes: Indeed conclude from this.

Somewhat related to the case of the barrel discussed earlier which was a case of moving an object without liability, the Gemara cites that Rav Yehuda said: That bundle of reeds that he stood upright and threw down, stood upright and threw down repeatedly, he is not liable for carrying it four cubits in the public domain until he lifts it off the ground. As long as he did not lift it from the ground, even though he moved it a long way, he did not perform the acts of lifting and placing which are prohibited by Torah law, as at least one part of the bundle always remained on the ground.

The Master said: A person standing on the threshold may take an object from the homeowner standing in the private domain and may give an object to him. Similarly, while standing there, he may take an object from a poor person standing in the public domain and may give an object to him because there is no element of prohibition or liability in carrying in and carrying out in an exempt domain on Shabbat. The Gemara asks: This threshold, what is it; to what type of threshold is it referring? Different thresholds have different halakhic status.

If you say that it is referring to a threshold that is the public domain, i.e., the threshold of an alleyway that is fewer than three handbreadths off the ground and is not covered, and the post that demarcates the parameters of the alleyway is situated between the public domain and the alleyway, how can the Tosefta say that he may take an object from the homeowner? Isn’t he carrying out from the private domain to the public domain?

Rather, say that the Tosefta is referring to a threshold that is the private domain, in a case where it is covered, or it is situated between the post that demarcates the parameters of the alleyway and the private domain, or it is ten handbreadths high and its area is at least four by four handbreadths. How then can the Tosefta say that he may take an object from a poor person? Isn’t he carrying in from the public domain to the private domain?

Rather, say that the Tosefta is referring to a threshold that is a karmelit, i.e., it is not ten handbreadths high and it is four by four handbreadths; how can the Tosefta say that he may take and give even ab initio? Ultimately, in this case, there is nevertheless a prohibition. Even though a karmelit does not engender liability by Torah law, carrying from it is prohibited by rabbinic law and is certainly not permitted ab initio.

Rather, say that the Tosefta is referring to a threshold that is merely an exempt domain, and therefore there is no prohibition at all. In what circumstances is it an exempt domain? In a case where it does not have an area of four by four handbreadths, and it is therefore not considered a domain with regard to liability on Shabbat. And that halakha is similar to that statement made when Rav Dimi came from Eretz Yisrael to Babylonia and he said that Rabbi Yoḥanan said: A place that does not have an area of four by four handbreadths and is set apart, it is permissible for both the people of the private domain and for the people of the public domain to adjust the burden on their shoulders upon it on Shabbat, as long as they do not exchange objects between them from one domain to the other domain.

The Master also said in the Tosefta: A person standing on the threshold may take an object from the homeowner and give an object to him, and he may take an object from the poor person or give an object to him, as long as he does not take the object from the homeowner and give it to a poor person or from a poor person and give it to the homeowner. And, however, if he took an object from one and gave it to the other, certainly no labor prohibited by Torah law was performed in that case, and all three of them are exempt. The Gemara asks: Say that this will be a conclusive refutation of Rava’s opinion, as Rava said: One who transfers an object from the beginning of four cubits to the end of four cubits in the public domain, even though he transferred it above the upper boundary of the public domain