1) GETTING THE BODY OF OG THROUGH A DOOR
QUESTION: Normally, when there is a dead person in a house, the utensils in all of the doorways become Tamei. This Tum'ah can be averted in one of three ways:
First, if one of the doorways is four Tefachim wide and all the others are smaller, then only the utensils in the four-Tefach doorway become Tamei. The utensils in all of the other doorways remain Tahor.
Second, if all of the doors are larger than four Tefachim but one is open and the others are closed, only the utensils in the open doorway become Tamei.
Third, if all of the doors are larger than four Tefachim, but the owner of the house decides to remove the dead person through a particular doorway, only the utensils in that doorway become Tamei.
The Gemara says that the Halachah regarding the Tum'ah caused by a corpse in a house is different for a very large body, such as that of Og Melech ha'Bashan (see Berachos 54b), than for all other bodies. To what Halachah does this statement refer? If only one doorway is larger than four Tefachim, then all of the smaller doorways should remain Tahor regardless of how large the body is (since it is logical to assume that the body will be taken out through the large doorway). If all of the doorways are larger than four Tefachim wide, then they all should be Tamei regardless of the size of the body.
ANSWERS:
(a) RASHI explains that this Halachah was said as a stringency (l'Chumra). Normally, when there are many doors of the same size, and a person opens one of the doors (the second case above) or decides to remove the body through a particular door (the third case above), all of the other doorways become Tahor. With regard to a body the size of Og Melech ha'Bashan, however, it does not suffice to open a door or to think about one of the doors; one must open or think about a door that is as large as the body in order for all of the other doorways to be Tahor.
(b) The RITVA says that this Halachah was said as a leniency (l'Kula). If all of the doorways are more than four Tefachim wide, but one door is as big as Og, then only that doorway is Tamei. Even though the other doorways are four Tefachim wide, they remain Tahor, since it is not possible to take Og's body through them. A normal-sized body, however, will be Metamei all of the doorways, even if one of them is much larger than the others.
2) "SINAI" SAID...
QUESTION: The Gemara asks how many raw eggs are needed to make an Eruv. Rav Nachman says that "Sinai" said that two eggs are needed. RASHI explains that "Sinai" refers to Rav Yosef, as the Gemara in Berachos (64a) and Horayos (14a) calls him. Why does Rav Nachman prefer to call Rav Yosef "Sinai" here, and not refer to him by name as he normally does?
ANSWERS:
(a) The BECHOR SHOR explains as follows. The Gemara in Pesachim (109b) says that it is a Halachah l'Moshe mi'Sinai that it is harmful to eat two eggs (because demons harm those who eat "Zugos," pairs, of certain foods; see Insights there). How, then, can the Shi'ur for making an Eruv with eggs be two eggs? The Eruv would be "Zugos" which may not be eaten! (This question is asked by the BESAMIM ROSH #183.)
According to one opinion in Pesachim (ibid.), the reason why the third and fourth cups of wine at the Pesach Seder are not considered "Zugos" is because the third cup is a Kos Shel Berachah, a cup used for a Mitzvah (for Birkas ha'Mazon). In Eruvin (31a), Rav Yosef states that an Eruv may be made only for the sake of a Mitzvah (such as in order to walk more than 2000 Amos to learn Torah on Shabbos). Accordingly, whenever a pair is eaten for the sake of a Mitzvah, there is no concern that it will bring harm to the person.
Two eggs can be used to make an Eruv, and there is no problem of "Zugos" because the Eruv is made for the sake of a Mitzvah. However, who has the credentials to state that the Halachah l'Moshe mi'Sinai that it is harmful to eat a pair of eggs does not apply to a pair eaten for the sake of a Mitzvah? Rav Nachman tells us that it is one of the foremost experts in the intricacies of Halachos l'Moshe mi'Sinai -- Rav Yosef. Rav Nachman therefore refers to him as "Sinai" (for Rav Yosef was an expert in Halachos l'Moshe mi'*Sinai*), to indicate that Rav Yosef is qualified to teach that "Zugos" does not apply to objects used for Mitzvos.
(The RASHASH and the GRIV question this explanation. An Eruv is made with the amount of food used for two meals. There should be no problem with an Eruv made from two eggs, because only one egg will be eaten at each meal.)
(b) The Gemara earlier (28a) cites a Beraisa that says that the minimum amount of Ma'aser Ani that one must give to a poor person on the threshing floor is two pomegranates. If Rav Nachman would have said that "Rav Yosef said two eggs," one would have assumed that since two pomegranates must be given as Ma'aser Ani, Rav Yosef infers by comparison that two eggs must be used to make an Eruv Techumin. That assumption is a mistake, though, because Rav Yosef himself became upset when Rav Menashya said that the laws in the Beraisa (with regard to Ma'aser Ani) apply equally to Eruv Techumin. In order to prevent this mistake, Rav Nachman refers to Rav Yosef as "Sinai" to imply that he was an expert in all of the Beraisos (as Rashi points out) and that he must have found an explicit source that teaches that the Shi'ur of an Eruv is two eggs. (M. KORNFELD)

30b----------------------------------------30b

3) THE AMOUNT OF FOOD NEEDED TO MAKE AN ERUV
QUESTION: The Gemara cites the Mishnah in Kelim (17:11) which says that a person makes an Eruv with the amount of food that he normally eats ("ha'Kol l'Fi Mah she'Hu Adam"). The Gemara says that the Mishnah there follows the opinion of Sumchus, who states in the Mishnah here (26b) that the food that one uses to make an Eruv must be fit for that person to eat.
The Gemara then points out that the Mishnah in Kelim refers only to a sick person or an elderly person, and therefore teaches a leniency. A sick or elderly person may rely on the amount of food that he normally eats, even though it is much less than the amount that a healthy person eats.
According to the Gemara's conclusion, how do we know that the Mishnah in Kelim follows the opinion of Sumchus? The Rabanan, who argue with Sumchus, say that one may even make an Eruv with food that another person can eat (even if he himself does not eat it). They certainly agree that a person is permitted to use the amount of food that he eats himself.
ANSWERS:
(a) TOSFOS (DH Targuma) answers that the Mishnah in Kelim implies that it suffices to use a small amount of food for a sick or elderly person regardless of the type of food. According to the Rabanan, if the person is sick or old, he may not use a small amount of healthy man's food (which is not fit for the sick or old person because it is food for the healthy, but it also is not fit for a healthy person because it is such a small amount). Therefore, the Mishnah must be in accordance with Sumchus, who does not allow a healthy man's food to be used for a sick person at all. Thus, a small amount suffices, regardless of what type of Eruv-acceptable food is being used.
(b) Tosfos answers further that when the Mishnah says that a person makes an Eruv with the amount of food that he normally eats, it does not mean that only a sick or elderly person uses the amount that he normally eats. It means that even a Yisrael must use only the food that is fit for him to eat (that is, he may not use Terumah). The Mishnah, therefore, cannot follow the opinion of the Rabanan, who maintain that a Yisrael may use Terumah to make his Eruv.
When the Gemara concludes that the Mishnah in Kelim refers to a sick or elderly person, it simply means that the Mishnah does not refer to a Ra'avtan (glutton). Such a person is "Batlah Da'ato Etzel Kol Adam" and does not need to use the large amount of food that he normally eats, even according to Sumchus. However, with regard to permissible or forbidden foods, the Mishnah in Kelim allows one to make an Eruv only with foods that are permissible to the one making the Eruv. (See also RASHASH.)

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