Siman - Eruvin Daf 4
- Parts of the mizbayach measured with five tefachim amos
Rabban Shimon ben Gamliel stated in a Baraisa, כל אמות שאמרו חכמים בכלאים באמה בת ששה ובלבד שלא יהו מצומצות – All the amah-units the Chochomim mentioned in regard to kilayim are measured using an amah of six tefachim provided that they should not be precise, meaning that they should be loose tefach-amos. The Gemara suggests that stipulating that kilayim require six tefachim amos, implies that Rabban Shimon ben Gamliel holds that with regards to a sukkah and a mavoi, five tefachim amos are used, which would support Abaye’s position.
The Gemara answers that Rabban Shimon ben Gamliel may have come to exclude the amah-units mentioned in context of the יסוד המזבח, הסובב, הקרנות, ומזבח הזהב – the base, ledge and horns of the mizbayach, as well as width and depth of the golden mizbayach ,which were all measured using five tefachim amah-units.
- חציצין הלכה למשה מסיני
Rebbe Chiya bar Ashi said in the name of Rav, שיעורין חציצין ומחיצין הלכה למשה מסיני – standard measurements, interpositions and partitions are all laws which were given orally to Moshe at Har Sinai.
After proving that the laws of חציצין - interpositions are in fact d’Oraysa, and that hair is also chotzeitz d’Oraysa, the Gemara clarifies that Rav was referring to a halacha which[AG1] Rebbe Yitzchok taught, דבר תורה רובו ומקפיד עליו חוצץ – According to Torah law, (meaning Halacha l’Moshe m’Sinai), something on one’s hair is only a chatzitza if it covers the majority of the hair, and if one objects to it being there. Rashi gives the examples of dried blood, ink, clay or tar. Rashi also explains that if one does not object to the object being on his hair, it is considered as part of the body.
The Rabbanon decreed that even if only one factor exists, meaning it covers most of one’s hair, or if he objects to it being on his hair, the tevillah is invalid.
- מחיצין הלכה למשה מסיני
The Gemara challenges Rav’s assertion that the halacha of mechitzos is a halacha l’Moshe m’Sinai from one of Rav’s own teachings in which he states that we derive the law that a mechitzah is ten tefachim from the fact that the aron was nine tefachim and the kapores was one tefach, for a total of ten tefachim.
The Gemara answers that Rav was referring to the view of Rebbe Yehudah who holds that the height of the aron was only seven and a half amos, and therefore it cannot serve as the source for mechitzos.
According to Rebbe Meir, the halacha l’Moshe m’Sinai is coming to teach the halachos of גוד, - extending a wall up or down, לבוד, viewing small gaps in a wall as closed, and דופן עקומה – the law of a bent wall of a sukkah.
