FOODS AND MATERIALS THAT JOIN
(Mishnah): Orlah (fruits of a tree in the first three years) and Kil'ai ha'Kerem (crossbreeds in a vineyard) join with each other (to be lashed for eating a k'Zayis);
R. Shimon says, they do not join.
(Gemara) Question: R. Shimon does not need them to join. He holds that one is lashed for any amount of Isurim!
Answer: Indeed, he means that they do not need to join.
(Mishnah): (The Shi'urim to receive (regular) Tum'ah for fabric, sackcloth, leather and matting are, respectively, three fingers (by three fingers), four Tefachim (by four Tefachim), five Tefachim and six Tefachim. Something fitting to lie or sit on receives Tum'as Mishkav u'Moshav. It can become an Av ha'Tum'ah if a Zav or Nidah sits on it.) The following join (for the Shi'ur) -- fabric and sackcloth, sackcloth and leather, leather and matting. (Here, the Bartenura says that all the materials join to comprise the largest Shi'ur among them. In Kelim (27:4) he says (regarding garments) that only the pairs listed join, i.e. each with the material with the next largest Shi'ur.)
R. Shimon says, they join because a common Shi'ur of Moshav applies to all of them:
(Gemara - Beraisa): If one cut from all (Rambam - from any one) of them and made a garment for Mishkav, it must be three Tefachim (to be Mekabel Tum'ah. The garment was cut smoothly, therefore a smaller Shi'ur applies);
If it was for a Moshav (a seat), it must be one Tefach. If it was for a handle, any size (Rambam - at least three fingers) is Mekabel Tum'ah.
Question: What kind of handle is discussed?
Answer #1 (Reish Lakish): It is a protection (from the threads that are tightened around the fingers) put on the fingers of weavers;
Answer #2 (Beraisa): It is put over the hands of those who harvest figs (to keep their hands clean; Pirush Kadmon (A) - alternatively, so their hands will not get cut).
DOES ME'ILAH DEPEND ON PEGAM?
(Mishnah - R. Akiva): One who benefits a Shavah Perutah from Hekdesh is Mo'el, even if he is not Pogem the item (decrease its value);
Chachamim say, if the Hekdesh item is subject to be Nifgam, he is not Mo'el unless he is Pogem. If it is not normally Nifgam, he is Mo'el once he benefits.
One is Mo'el in the following cases of benefit from Hekdesh (if one would pay a Perutah to rent such an object of Chulin);
One wore a choker (tight necklace) on her neck, or a ring on her finger, or drank from a gold cup.
In the following cases, one is not Mo'el unless he is Pogem --
He wore or covered himself with a garment, he chopped with an axe.
If one benefits from a live Chatas, he is not Mo'el unless he is Pogem;
If he benefits from a dead Chatas, he is Mo'el for benefit in any case.
(Gemara - Beraisa): R. Akiva agrees regarding something that is prone to be Nifgam.
Question: If so, what do they argue about?
Answer (Rava): They argue about (things that are not perceivably Nifgam for a long time, e.g.) an intermediate garment (it is not external, nor next to the skin) or a fine linen garment (one wears it only rarely. Most Rishonim - R. Akiva considers such things as if they are not prone to Pegam. R. Gershom - they are considered prone to Pegam. It is if he benefited and was Pogem.)
(Beraisa): "Nefesh" (in the verse discussing Me'ilah) refers to a commoner, Nasi (king) or Mashu'ach (anointed Kohen Gadol);
"Ki Sim'ol Ma'al" refers to Shinuy (change, from Hekdesh to Chulin);
We learn from "Ish Ish Ki Sisteh Ishto u'Ma'alah Vo Ma'al" and "va'Yim'alu b'Elokei Avoseihem va'Yiznu Acharei Elohei Amei ha'Aretz." (These are written regarding Sotah and idolatry.)
THE GEZEIRAH SHAVAH FROM TERUMAH
Suggestion: Perhaps Me'ilah applies in the following cases:
One was Pogem without deriving benefit, or benefited without Pegam;
The Hekdesh was attached to the ground;
Version #1 (our text): A Shali'ach fulfilled his mission. (Perhaps the Shali'ach was Mo'el.)
Version #2 (Bach): A Shali'ach did not fulfill his mission. (Perhaps the sender was Mo'el.)
Rejection: We learn from a Gezeirah Shavah. It says "Chet" regarding Me'ilah, just like regarding Terumah. (It says "Chet" regarding a Tamei who eats Terumah (Vayikra 22:9) and regarding separating Terumah (Bamidbar 18:32). The Rishonim say that we learn from a Zar who ate Terumah b'Shogeg, which following the former verse.)
Regarding (eating) Terumah there is Pegam and benefit, the one who was Pogem benefited from what was Nifgam, the Pegam and benefit came at the same time, the benefit was from something detached, and Shelichus (to separate Terumah) works only if the Shali'ach fulfilled his mission. Likewise, Me'ilah applies only when all of these are fulfilled. (Regarding Shelichus, the sender was Mo'el if the Shali'ach fulfilled his mission. If he deviated, the Shali'ach was Mo'el.)
(R. Gershom's text) Question #1: We know that one is Mo'el only if he ate. What is the source that one who benefited from Hekdesh not prone to Pegam was Mo'el?
Question #2: What is the source that what Reuven ate or benefited from joins with what (he gave to Shimon and) Shimon ate or benefited from to make Reuven liable for Me'ilah, even over a long period of time? (Tosfos - we must say that Reuven put the food in Shimon's mouth, or commanded Shimon to take the food, causing Shimon to acquire it before eating it. Keren Orah - really, Question #2 concerns only joining Shimon's benefit (benefit over a long period is mentioned only by the way). Question (g) addresses benefit over a long period, and Question (j) concerns joining benefit in different years, i.e. Yom Kipur does not atone for a partial Shi'ur of Me'ilah.)
Answer (to both questions): "Sim'ol Ma'al" includes these.
Suggestion: Achilos (acts of eating) of Terumah at different times (not within Kedei Achilas Pras) do not join (to comprise a Shi'ur) -- perhaps the Gezeirah Shavah teaches that the same applies to Me'ilah;
Question: What is the source that Achilos join for Me'ilah, even on different days or after a long time?
Answer: "Sim'ol Ma'al" includes this.
Suggestion: One is liable for (eating) Terumah only if Pegam and benefit came together. Perhaps the Gezeirah Shavah teaches that the same applies to Me'ilah;
Question: What is the source to join what Reuven ate (with what Shimon ate; some delete this. It is not in the text in Toras Kohanim), even over a period of three years (or more)?
Answer: "Sim'ol Ma'al" includes this.