Siman - Eruvin Daf 43
- Do the halachos of techum apply above ten tefachim?
Rav Chananya asked, יש תחומין למעלה מעשרה או אין תחומין למעלה מעשרה– Do the halachos of techum apply above ten tefachim or not? If they do not apply, then it would be permitted for someone to travel beyond the techum at a height above ten tefachim.
The Gemara attempts to prove that the laws of techum do not apply above ten tefachim from an incident where seven rulings that were said on Shabbos morning before Rav Chisda in the town of Sura were repeated Shabbos afternoon before Rava in Pumbedisa, which is at a greater distance than the techum. The Gemara suggests that it must have been Eliyahu HaNavi who travelled in the air above ten tefachim and reported the teachings, which proves techumin do not apply above ten tefachim, since he would not violate Shabbos. This proof is rejected as the Gemara suggests that it might have been Yosef Shida, Yosef the demon, who travelled beyond the techum because he is not shomer Shabbos.
- Why the Moshiach will not come on Shabbos
The Gemara then attempts to prove that the laws of techum do apply above ten tefachim based on a Baraisa that teaches that if someone declared, הריני נזיר ביום שבן דוד בא – “I am a Nazir effective on the day that Moshiach comes”, מותר לשתות יין בשבתות ובימים טובים – he is permitted to drink wine only on Shabbos and Yom Tov. Rashi explains that it is certain that Moshiach will not arrive on those days.
The Gemara suggests that the reason the Moshiach will not come on Shabbos and Yom Tov is that he will not violate the laws of techum and travel more than two thousand amos. If the laws of the techum do not apply above ten tefachim then it would still be possible for the Moshiach to arrive on Shabbos by travelling in the air above ten tefachim, and the Nazir should not be permitted to drink wine on Shabbos. This seem to prove that the techum does apply above ten tefachim.
The Gemara gives a different reason for why the Moshiach will not come on Shabbos and Yom Tov. The passuk in Malachi states that Eliyahu HaNavi will be sent to announce the pending arrival of Moshioch the day before, and כבר מובטח להן לישראל שאין אליהו בא לא בערבי שבתות ולא בערבי ימים טובים מפני הטורח – There is a tradition that Eliyahu will not arrive on Shabbos or Yom Tov because of the difficulties it would impose on people to complete their preparations will taking time to great Eliyahu.
- שפופרת
The Gemara brings a Baraisa that teaches that Rabban Gamliel used a שפופרת on the boat, a hollow tube with which he was able to look and sight a distance of two thousand amos on land or at sea. Rashi explains that a long hollow tube narrows and shortens the viewers range and can be calibrated to yield a maximum distance of two thousand amos. The Baraisa brings additional innovative ways to calculate measurements.
