A MECHITZAH THAT CAME ABOUT BY ITSELF
(Abaye): A Lechi that came about by itself (it was not made for this purpose) is a [valid] Lechi;
(Rava): It is not a Lechi.
All agree that if we did not rely on it from before Shabbos (e.g. there was another Lechi) that it is not a Lechi;
They argue about when we relied on it from before Shabbos. Abaye is Machshir, for we relied on it from before Shabbos;
Rava is Posel, because it was not initially made to be a Lechi.
We are thinking that they likewise argue about a Mechitzah that was not built to be a Mechitzah. (All of the following questions are against Rava.)
Question (Mishnah): If one built a Sukah between trees, and they are its walls, it is Kosher.
Answer: The case is, they were planted for this purpose.
Question: If so, obviously it is Kosher!
Answer: One might have thought that we decree to forbid, lest one use a tree [on Shabbos or Yom Tov]. The Mishnah teaches that we do not decree.
Question (Beraisa): If there is a tree, fence or Chitzas ha'Kanim (reeds growing out of a common stump) where one wants to put Pasei Bira'os (planks surrounding a well, which permit carrying inside - 17b), one may use them for the corner posts.
Answer: Here also, they were planted for this purpose.
Question: If so, obviously one may use them!
Answer: The Chidush is that the reeds are separated by less than three Tefachim (we rely on Lavud), like Abaye's question (19b. The Chidush of the tree can be like above (h), or that we consider it as if it was carved to the proper shape.)
Question (Mishnah): If the foliage of a tree hangs within three Tefachim of the ground, one may carry under it.
Answer: Here also, it was planted for this purpose.
Question: If so, there should be no limit to the area enclosed. However, Rav Huna brei d'Rav Yehoshua taught that one may carry only if the area is at most Beis Sa'atayim (5000 square Amos)!
Answer: That is because it is a Dirah for the sake of Avir (what is outside itself, e.g. to guard produce). One may not carry in such a Dirah if it exceeds Beis Sa'atayim.
Question (Beraisa): If one made his Shevisah (residence for Shabbos) on a mound 10 Tefachim tall extending between four Amos and Beis Sa'atayim, or in a cleft in a rock 10 deep and four wide, or in a harvested area surrounded by [attached] sheaves (10 Tefachim tall and tied so they do not blow in the wind - Mishnah Berurah), he may traverse the entire place and 2000 Amos in every direction.
Suggestion: Here also, they were made for this purpose.
Rejection: This could answer for sheaves, but not for a mound or cleft! (They were there from Creation.)
A LECHI THAT CAME ABOUT BY ITSELF
Retraction: Rather, Rava agrees that a Mechitzah need not be made for that purpose. He argues only about a Lechi:
Also elsewhere (5a), Abaye holds that a Lechi is considered a Mechitzah. Therefore, it need not be made for this purpose;
Also elsewhere (12b), Rava holds that a Lechi is a Heker. It is a Heker only if it was made for this purpose.
Question (Beraisa): If rocks jut out of a stone wall (they are staggered, one on top of another; the top one is at least 10 Tefachim high), another Lechi is needed only if there is three Tefachim between two successive rocks or between the bottom rock and the ground.
Answer: Here also, [we assume that] they were built this way for this purpose.
Question: If so, obviously it is Kosher!
Answer: One might have thought that they were built to enable extending the wall. The Beraisa teaches that this is not so.
Question (R. Chiya - Beraisa): If one side of [the thickness of] a wall is recessed from the other, whether it is Nir'eh miba'Chutz v'Shavah mibi'Fnim or Nir'eh mibi'Fnim v'Shavah miba'Chutz, it is considered a Lechi.
Answer: Here also, it was built this way for this purpose.
Question: If so, obviously it is Kosher!
Answer: The Chidush is that Nir'eh miba'Chutz v'Shavah mibi'Fnim is considered a Lechi.
Question: A case occurred in which Rav was sitting in a Mavoy and asked his attendant to bring a cup of water. Before he returned, the Lechi fell. Rav gestured to the attendant to stand still.
Rav Huna: Why don't you rely on the date tree for a Lechi?
Rav: That was a foolish suggestion. We did not rely on it from before Shabbos!
Inference: Had they relied on it from before Shabbos, it would be a Lechi! (We ask from Rav like from a Beraisa, for all Chachamim of Bavel were Talmidim of Rav or Shmuel, or of later generations of their Talmidim.)
Suggestion: Abaye and Rava argue about when one did not rely on it from before Shabbos, but if he did, all agree that it is a Lechi!
Rejection: A beam supporting a certain shed was at the end of a Mavoy, and Abaye and Rava argued about it their entire lifetimes. (We concluded like Abaye. This is one of the six places where the Halachah follows Abaye against Rava.)
THINGS FOR WHICH LIVING BEINGS MAY NOT BE USED
(Mishnah): A Lechi may be made of anything, even if it is alive;
R. Meir forbids something alive.
If something alive was used for a Golel (Rashi - a coffin cover; Tosfos - a monument marking the location of a grave), it is Metamei;
R. Meir is Metaher.
One may write a Get (divorce document) on something alive;
R. Yosi ha'Gelili disqualifies such a Get.
(Gemara - Beraisa - R. Meir): Something alive cannot be used for a Sukah wall, a Lechi, Pasei Bira'os, nor a Golel for a grave;
R. Yosi ha'Gelili says, also, one may not write a Get on it.
Question: What is his reason?
Answer (Beraisa) Question: [One divorces with a] "Sefer." What is the source to include [writing on] anything?
Answer: "V'Chosav Lah" includes everything.
Question: If so, why does it say "Sefer"?
Answer: This teaches that a Get must be written on something like a Sefer, i.e. it is not alive and it is not a food.
Chachamim: Had the Torah said "b'Sefer", we would agree. However, it says "Sefer." This refers to Sefiras Devarim. (The Get must tell how he divorces her.)
Question: What do Chachamim learn from "v'Chosav Lah"?
Answer: This teaches that he divorces through writing, and not through money;
One might have thought that since a verse equates divorce to engagement; just like money can be Mekadesh, it can divorce. The verse teaches that this is not so.
R. Yosi ha'Gelili learns this from "Sefer Kerisus" - only a Sefer severs [marriage];
Chachamim learn from "Sefer Kerisus" that the Get must cut them off from each other. (It cannot have a condition that she must guard for the rest of her life);
(Beraisa): A divorce 'on condition that you will never drink wine', or 'on condition that you will never go to your father's house' is invalid;
If the condition is only for 30 days, the Get is valid.
R. Yosi ha'Gelili expounds the plural "Kerisus" to teach [also] this. It could have said 'Kares' to teach [only] the above law;
Chachamim hold that the plural form does not warrant teaching another law.
(Mishnah): If a caravan camped in a valley and surrounded it with Kelim used for animals (e.g. saddles; even though one is not Mevatel them, it is a Mechitzah - Tif'eres Yisrael), one may carry inside, as long as it is 10 Tefachim tall and the area of the gaps does not exceed that of the Kelim;
A gap up to 10 Amos is permitted. More than this forbids.
(Gemara - Rav Papa): Parutz k'Omed (the width of the gaps equals that of the wall) permits;
(Rav Huna brei d'Rav Yehoshua): It does not permit.
Rav Papa permits. He holds that Hash-m taught Moshe that if the majority is open, it is not a Mechitzah;
Rav Huna permits. He holds that Hash-m taught Moshe that if the majority stands, it is a Mechitzah. (The following questions are against Rav Huna.)
Question (Mishnah): The gaps cannot exceed the width of the Kelim.
Inference: If they are equal, it is permitted!
Answer: It should say, if the width of the Kelim exceeds that of the gaps, it is permitted.
Question: This implies that if they are equal, it is forbidden. If so, it should have said 'as long as the gaps are not as much as the Kelim'!
This is left difficult.
Question (Mishnah): If one roofed his Sukah with roasting spits or bed boards [which are Pasul for Sechach], if the spaces between them are as big as them [and are covered with Kosher Sechach], it is Kosher. If not, it is Pasul.
Answer: The case is, there is room between spits to insert and remove spits with leeway. (I.e., the spaces are slightly bigger.)
Version #1 (Rashi) Objection: It is possible to make the spaces equal the spits! [Therefore, surely they are equal, like the Mishnah says.]
Answer #1 (R. Ami): He [intentionally] left room between spits to insert and remove spits with leeway.
Version #2 (Tosfos) Objection: It is impossible to totally fill all the spaces [with Kosher Sechach. Therefore, it is the minority. Everyone should disqualify the Sukah!]
Answer #1 (R. Ami): He puts extra layers of Kosher Sechach. In this way one can fill all the spaces. (end of Version #2)
Answer #2 (Rava): The Kosher Sechach is placed perpendicular to [and on top of] the Pasul Sechach. (It must be bigger in order to stay up.)