As we have discussed on the previous dapim, both a person and his possessions are limited by the rules of tehumim (boundaries) on Shabbat and Yom Tov. Therefore, a person cannot walk more than 2,000 cubits outside of his city on Shabbat or Yom Tov. By creating an eiruv tehumim – a meal placed on the perimeter of the 2,000 cubit limit – he can extend the area that he is permitted to walk 2,000 cubits in that direction (although what he has actually done is shifted the circle in which he is permitted to travel so that its center is no longer in the city, but at one edge of the city limits).
The Mishna on our daf teaches that a person who has guests come and visit on Yom Tov from the next city (i.e. they created an eiruv tehumim that allowed them to travel to him; he did not create such an eiruv so neither he nor his possessions can go to their city), cannot give them food to take back home with them, since the food belongs to him and is therefore limited to areas that he is allowed to go to.
The Gemara relates: Rav Hana bar Hanilai once hung meat on the bar of the door of his host’s house, located outside his own town. He subsequently wondered if he was permitted to take the meat home with him, since he had made an eiruv enabling him to walk from his home to his host’s home. He came before Rav Huna to ask his opinion. Rav Huna said to him: If you yourself hung the meat, go take it, but if your hosts hung it for you, you may not take it.
From this story, the Gemara wants to try to prove a number of issues regarding the rules of tehum and eiruv on Yom Tov. Its conclusion, however, is that Rav Huna’s ruling did not involve rules of tehum and eiruv and was unique to Rav Hana bar Hanilai who was such a scholar that he regularly focused on his Torah study and paid little attention to mundane goings on around him. Rav Huna ruled that if he had placed the meat on the door himself, he probably had paid attention to it, so it was fine, but if his hosts had put it there, he did not pay sufficient attention to it, and it could not be used.
Rashi explains that the concern here was for basar she-nitalem min ha-ayin – meat that was not under constant watch. This rule stems from a concern lest the meat be switched with non-kosher meat so the Sages ruled that when such a switch can occur, meat needs to be under constant supervision or else have a symbol attached to it so that it can be recognized as kosher meat. The Me’iri suggests that had he placed the meat on the door he could be certain that it was in the place and position that he had put it, which would have solved the problem. In any case, the Gemara concludes that no rules about tehum and eiruv can be derived from this story, which was concerned with an entirely different matter.