1) "FORTY MINUS ONE"
QUESTION: The Mishnah says that the number of Melachos are "forty minus one." Why does the Mishnah not say simply that there are "thirty-nine" Melachos?
(a) The TOSFOS YOM TOV suggests that since the maximum number of lashes that a person can receive is called "forty minus one" (Makos 22a), the Melachos are also called "forty minus one." (The Mishnah refers to lashes as "forty minus one" and not "thirty-nine" because the Torah uses the word "forty" to refer to them.)
(b) The son of the TOSFOS YOM TOV suggests an answer based on the Gemara earlier (49b). The Gemara there says that the number of Melachos prohibited on Shabbos is derived from the number of times that the word "Melachah" appears in the Torah. The Gemara asks that the word "Melachah" actually appears forty times, and the Gemara answers that one of them is not counted. The Mishnah alludes to this by saying that there are "forty minus one" Melachos.
(c) The TOSFOS YOM TOV suggests another answer. The Gemara says later (74b; see RASHI there, DH v'Iy Chayetei) that one is Chayav for the Melachah of Tofer (sewing) only if he ties a knot at the end of the stitching so that it does not unravel. Therefore, practically speaking, it is not possible to transgress the Melachah of sewing without also transgressing the Melachah of tying, in which case he has done forty Melachos (all 39, plus an extra one of tying in order to complete the Melachah of sewing). The Mishnah alludes to this by saying that there are "forty minus one" Melachos. (One might ask that it is indeed possible to limit one's transgressions to 39, if one first sews a stitch, and then ties a knot to hold the stitch in -- without tying any other knots. In that case one does only 39 Melachos, and not 40! The Tosfos Yom Tov must mean that the Melachos cannot be done in the order of the Mishnah unless one does a total of forty Melachos.)
(d) The MAYIM CHAYIM answers based on the Gemara (73b) which notes that the Melachah of plowing that is mentioned in the Mishnah is done after the Melachah of sowing. Although a person usually plows the land before sowing as well as after sowing, the Mishnah refers only to the second plowing, which is done when the soil is hard after the seeds have been sown. Accordingly, when one does all of the Melachos mentioned in the Mishnah, he does forty Melachos (that is, two plowings, one before sowing and one afterwards). The Mishnah alludes to this by saying that there are "forty minus one" Melachos.
2) AN "AV MELACHAH"
OPINIONS: The Mishnah teaches that there are thirty-nine Avos Melachos. What makes an act an Av Melachah?
(a) RASHI (DH Ofeh) says that anything that was done for the construction of the Mishkan is an Av Melachah.
We may ask that the verse says that all of the materials necessary for the construction of the Mishkan were collected within two days after the people were commanded to build the Mishkan. How, though, could they have prepared the herbs and plants used for the dyes in just two days, if they needed to plow, sow, reap, and so on? The IGLEI TAL (Introduction, #2) infers from Rashi that any act that was necessary to perform in order to obtain a material needed for the Mishkan is a Melachah even though it was not done for the Mishkan when it was actually constructed (but rather they used materials that they had brought with them from Mitzrayim, or had acquired in the Midbar).
(b) However, the RAMBAN (74a) writes that only labors that were performed by the Jews explicitly for the sake of the Mishkan are considered Melachos. This is supported by the wording of the Gemara earlier (49b), "Hem Zar'u v'Atem Lo Tizre'u" -- "Since they sowed, you shall not sow." How did they sow and reap in just two days? The AVNEI NEZER explains, based on the Midrash Rabah, that just as Yakov Avinu planted Arazim trees in Mitzrayim for the Mishkan and bid his children to take them out in order to build the Mishkan, so, too, he told them to plant and take out other materials for the Mishkan. Since the act of planting and other acts of preparation were done for the Mishkan (albeit in Mitzrayim), one is Chayav for doing such acts on Shabbos.
(c) The RAMBAM (Teshuvos #134) cites RAV HAI GA'ON who explains that any Melachah done for the purpose of baking (i.e., any of the first eleven Melachos listed in the Mishnah) that was done in order to prepare for offering the Korbanos and Menachos in the Mishkan is considered a Melachah -- even though it was not related to the construction of the Mishkan in any way. This is what the Gemara means by "Hem Zar'u v'Atem Lo Tizre'u," and by "Tana Sidura d'Pas Nakat" (Daf 74b). The AVNEI NEZER points out that Rashi later (92a, DH she'Ken Masa) also cites Rav Hai's opinion. Rashi records in the name of Rav Hai Ga'on a Yerushalmi that appears to lead to the same conclusion.
However, it is not clear why Rav Hai Ga'on learns only the Melachos of baking bread from the Korbanos of the Mishkan, and not the other Melachos (such as ha'Shochet, etc.). Perhaps Rav Hai Ga'on means merely to explain why the Mishnah lists Melachos of baking instead of Melachos of cooking (see Rashi in the Mishnah), and he does not mean that an activity can become a Melachah because it was done for the Menachos or Korbanos. (M. KORNFELD)
3) DIFFERENT FORMS OF "ZORE'A"
QUESTION: The Gemara concludes that "Zomer Chayav Mishum Note'a" (pruning is Chayav because of planting), and "Note'a, Markiv, and Mavrich Chayav Af Mishum Zore'a" (even planting, grafting, and bending a vine branch and planting it are Chayav because of sowing). RASHI explains that since those three (Note'a, Markiv, and Mavrich) are all forms of the Melachah of Zore'a, if one does all of them together with Zore'a, he is Chayav to bring only one Chatas.
This implies that if one does Zomer, which is Chayav only because of Note'a, together with Zore'a, he is Chayav to bring two Chata'os. However, the Gemara just stated that one who does all of these together is Chayav to bring only one Chatas!
(a) The RITVA explains that according to Rashi, one is indeed Chayav to bring two Chata'os, one for Zomer (which is Chayav because of Note'a) and one for Zore'a. However, if he does Zomer and Zore'a together with Note'a as well, he will be Chayav to bring only one Chatas, because Zomer is part of Note'a, while Note'a is identical to Zore'a (the only difference is that it is done with a sapling instead of a seed). Since Note'a and Zore'a are covered by one Chatas, Zomer -- which is a Toldah of Note'a -- is also covered by that Chatas.
(b) Rashi's words can be understood differently. When the Gemara says that Note'a, Markiv, and Mavrich are Chayav "Af Mishum Zore'a" (lit. "even because of Zore'a"), it does not mean that they are Chayav for both Note'a and Zore'a. Rather, they are Chayav only for Zore'a. "Af Mishhum Zore'a" means that even all of these are Chayav only for Zore'a (for we might have thought that they are their own independent Av Melachos and are Chayav for both themselves and for Zore'a; see Background to the Daf).
The Chidush of Zomer, on the other hand, is the exact opposite. It is obvious that Zomer is not an independent Av Melachah. We might have thought that Zomer is not Chayav at all because it does not resemble any form of planting (since when one prunes a tree, he does not place any object into the ground in order to grow). Therefore, Rav Ami teaches that Zomer is indeed Chayav for Note'a.
(c) TOSFOS, as quoted by the RITVA, disagrees with Rashi and says that the Gemara is discussing Hasra'ah (the warning given to someone before he commits a sin), and not the obligation to bring a Korban or multiple Korbanos. The Gemara teaches that one can be Chayav for Zomer only if he was warned with "Note'a" (i.e., the witnesses warned him and said, "You will be Chayav if you do that act because it is an act of Note'a!"). To be Chayav for Note'a, Markiv, and Mavrich, though, one can be warned for either Note'a or Zore'a (but one will always be Chayav to bring only one Korban, regardless of the act for which he was warned).
4) ONE WHO KNOCKS A DATE OFF A TREE
QUESTION: Rav Papa says that one who throws a rock or clod of earth at a date palm and knocks a date off is Chayav for two Melachos -- Tolesh (picking fruit off a tree) and Mefarek. RASHI explains that Mefarek in this context refers to taking the date out of its cluster. However, if this is true, then why is one not Chayav for Mefarek every time he removes a grape from a cluster (even if the cluster of grapes is not attached to the tree)? (SEFAS EMES)
(a) TOSFOS (DH v'Achas) and other Rishonim had a different text of Rashi. In their text, Rashi says that Mefarek refers to "unburdening" the tree from its burden (the dates).
However, the Rishonim reject this explanation, because we do not find that a person is Chayav for Mefarek every time he picks any type of fruit from a tree. He is Chayav only for Kotzer (Tolesh). According to this version of Rashi, since he unburdens the tree of its fruit, he should be Chayav for Mefarek as well.
(b) Tosfos explains in the name of the RASHBAM that the dates have an outer skin that comes off when they are knocked from the tree. Taking the dates out of their outer skin is the same action as Mefarek, taking a grain out of its sheath.
(c) The RAMBAN learns that pulling a date off of its cluster after it falls from the tree is called Mefarek. The Ramban seems to understand that the normal manner was to cut off the clusters of dates from the tree and then afterwards to separate dates from the cluster prior to selling them (in this respect it differs from grapes, because it is normal to sell grapes with their cluster). This may also be the intention of Rashi according to our version.