OPINIONS: The Mishnah (2a) teaches that in order for a Korah to permit one to carry in a Mavoy, the Korah at the top of the entrance to the Mavoy must not be higher than 20 Amos. If it is higher than 20 Amos, it is not noticeable and it fails to serve its purpose of reminding people that they are in a Mavoy. The Gemara quotes a Beraisa that says that if there is an "Amaltera" on the Korah, then the Korah may be higher than 20 Amos, since it attracts attention and people notice it. Rav says that another Beraisa (2b) argues and maintains that an Amaltera does not permit the Korah to be higher than 20 Amos. Rav Nachman bar Yitzchak says that the Beraisos do not argue; both Beraisos agree that an Amaltera permits the Korah to be higher than 20 Amos.

The Gemara quotes two opinions with regard to what an Amaltera is. According to one opinion, it is a decorative beam adorned with carved figures of birds' nests. According to another opinion, it is comprised of long strips of expensive cedar wood. According to the first opinion, only decorations of birds' nests constitute an Amaltera, since they are very decorative and eye-catching. According to the second opinion, strips of cedar wood catch the eye as well, since they are more costly than normal beams. What is the Halachic ruling?

(a) The RAMBAM (Hilchos Shabbos 17:15) rules that the Amaltera must be very eye-catching, such as a beam decorated with carved figures of birds' nests. (The DARCHEI MOSHE (OC 363) quotes the HAGAHOS ASHIRI, who explains that any unusual design on the Korah that attracts the attention of by-passers also constitutes an Amaltera.)

(b) However, the RASHBA, TUR (OC 363) and SHULCHAN ARUCH (OC 363:26) rule in accordance with the second opinion, that cedar beams also constitute an Amaltera. (It should be noted, however, that the BACH understands that the Tur rules like the Rambam. The Bach asserts that the Beis Yosef's understanding of the Tur is based on a typographical error.)

QUESTION: The Gemara initially assumes that cedar beams constitute a unique Korah because of their length. What is it about the length of cedar beams that is unique? RASHI implies that the cedar beams extend from one wall to the opposite wall of the Mavoy. However, every Korah extends from one side of the Mavoy to the other! What is unique about a Korah made of cedar beams? If the cedar beams are unique because they extend longer than the width of the Mavoy, their unique length is not evident to those standing inside the Mavoy! How, then, can they serve as a "Heker" for those standing inside the Mavoy?

(a) Perhaps the cedar beams indeed extend past the walls of the Mavoy, and they serve as a Heker because people standing outside of the Mavoy notice them and talk about them (they have a "Kol"). Consequently, even the people standing inside the Mavoy are aware of them, and thus they serve as a "Heker."

(b) Alternatively, perhaps Rashi means that the cedar beams extend outwards from the ends of the Mavoy walls, in addition to a separate Korah placed atop the walls. People notice the protruding cedar beams no matter how high they are, and their attention is then drawn to the Korah that marks the end of the Mavoy.

OPINIONS: Abaye and Rava argue about the size of the Amah used for various Halachos. Abaye says that some dimensions are measured with an Amah that is five Tefachim long, while others are measured with an Amah that is six Tefachim long. The Amah that produces the most stringent measure is the one used for any particular measurement.

Rava, on the other hand, maintains that all measurements use the six-Tefach Amah. The stringency of the measure is determined by whether it is an Amah "Sochekes" or an Amah "Otzeves" that is used. The RASHBA (Avodas ha'Kodesh 1:3:5) explains that the difference between an Amah Sochekes and an Amah Otzeves is half a fingerbreadth (Etzba). (There are four Etzba'os in a Tefach, and thus there are 24 Etzba'os in an Amah. Since the difference between the Amah Sochekes and the Amah Otzeves is half an Etzba, the Amah Sochekes is 1/48th longer than the Amah Otzeves.) The Rishonim explain that the Rashba's source is the Gemara in Pesachim (86b) which mentions an Amah that is half an Etzba longer than the normal Amah.

The Rishonim disagree about how we apply the stringency of using an Amah Sochekes or an Amah Otzeves according to Rava.

(a) The RASHBA (in Chidushei ha'Rashba) writes that according to Rava, the laws of Sukah, Mavoy, and Kil'ayim each use only one type of Amah. Sukah uses only the Amah Otzeves even with regard to the minimum length of a wall (even though the use of the Amah Otzeves results in a leniency). Mavoy, too, uses only the Amah Otzeves even with regard to the minimum length of a wall. Kil'ayim uses only the Amah Sochekes even for measuring the distance between rows of grapevines for the Halachah of "Retzufin." This also seems to be the opinion of RASHI (end of 3b and beginning of 4a).

The Rashba explains that support for this view can be inferred from the fact that the Gemara does not ask the same questions on the opinion of Rava as it asks on the opinion of Abaye. This indicates that Rava maintains that the standard measure used for all laws in each category follow the majority (Rov) of measures in that category. Abaye, in contrast, does not follow the majority of measures of each category. He applies whichever Amah is more stringent in each individual measurement, because he maintains that mid'Oraisa the Amah is six Tefachim long, and the Rabanan devised the five-Tefach Amah only as a stringency (where applicable).

How can Rava allow a person to be lenient with Mitzvos of the Torah? Apparently, he maintains that mid'Oraisa the Amah is six Tefachim long, but the Torah leaves it to the Rabanan to decide whether the Amah used for any particular measure is an Amah Sochekes or an Amah Otzeves. (For an example of this concept, see Chagigah 18a.) Alternatively, Rava maintains that the Torah allows for a flexible range of the Amah, including both the Amah Sochekes and the Amah Otzeves. The Torah calls both of them "Amah." (M. KORNFELD)

(b) The BA'AL HA'ME'OR and the RAMBAM (Hilchos Shabbos 17:36) argue with the Rashba. They rule in accordance with Rava, but they explain that Rava means that for each individual application we must use the Amah, either Sochekes or Otzeves, which is more stringent in that particular application, as Abaye says.