Two questions from the beginning of Moed Katan.
1. 3a Rashi D"H LO YIKASHKESH TACHAS HAZEISIM V'LO YE'ADER. Rashi notes
a discrepancy in the B'raiysa, the B'raiysa forbids IDUR and then permits
it. Rashi asserts that there are two types of IDUR, hoeing, done to a
ground that has never been hoed before which is assure and hoeing to
ground that has previously been hoed before which would be mu tar. Rashi
tells us that such a distinction is made on 4b albeit in a different
context. This seems problematic, looking at the gemorah on 4b, the
CHILUK of HA BRACHA V'HA B'ATIKI is made in the context of CHOL HAMOED
where such a distinction is understood as Rashi there himself explains,
if it is virgin soil it would require extra effort and thus forbidden on
CHOL HAMOED. However here on 3a the B'raiysa is discussing Shmitah and
there would seem to be no basis for such a distinction. Does a TIRCHA
Y'SEIRA make something ASSUR in SH"NAS HASHMITA?
2. 4a Rav Ashi explains the relationship between the HALACHA L'MOSHE
M'SINAI and the TAKANAH of R' Gamliel. The HL"M extends only as long as
the Temple is up , after which there is a TAKANAS CHACHAMIM which R'
Gamliel lifted. R Ashi proves his point from the fact that ESER N'TIYOS
is learned next to ARAVAH and NISUCH HAMAYIM which also are only while
the Temple is up. Tosfos explains that these three HL"M were taught to
Moshe together for exactly this reason. The Bach points out that Rashi
in Sukkah 34 seems to disagree, Rashi there asserts that the three
Halachos were bunched together because recording Tanah happened to hear
these halochos in the Beis Medrash together. How would Rashi learn the
proof of Rav Ashi in our Gemorah?
(a) Excellent question! In the Insights to Daf 2a (1:b), we cited the RITVA who maintains that doing a Melachah on the land which involves excessive Tircha is prohibited during Shevi'is just like it is prohibited during Chol ha'Mo'ed. The Ritva writes the same thing at the beginning of Daf 3a, when he says that Nichush is prohibited during Shevi'is because it involves excessive Tircha. It could be that this is what Rashi holds as well (as is pointed out in the footnotes to the Ritva (Mosad Ha'Rav Kook edition), #182. (Regarding the other Rishonim who argue with the Ritva, apparently they had a different Girsa in the Gemara and did not have the words, "Yachol... Lo Ye'ader ." Indeed, the Ritva himself omits these words, and so writes many Rishonim.)
(b) According to Rashi in Sukah, when the Gemara here says, "The Halachah l'Moshe mi'Sinai applies to when the Beis ha'Mikdash is standing, similar to [the Halachah l'Moshe mi'Sinai regarding] Nisuch ha'Mayim ," it does not mean to say that since all three Halachos were transmitted at the same time, they therefore all have the same realm of application. Rather, the Gemara means that since we find in one place that there is a Halachah l'Moshe mi'Sinai which is applicable only in the times of the Beis ha'Mikdash (i.e. Nisuch ha'Mayim), it makes sense to say that the Halachah l'Moshe mi'Sinai of Eser Neti'os is also limited to the times of the Beis ha'Mikdash, and does not apply to all generations. (This also explains why the Gemara does not say, "... similar to Nisuch ha'Mayim and Aravah ." According to Tosfos, the Gemara should have mentioned both, because Tosfos maintains that the proof for Eser Neti'os is from the fact that both Nisuch ha'Mayim and Aravah apply only in the times of the Beis ha'Mikdash. According to Rashi's understanding, though, it makes sense; the Gemara's intention is not to prove from the fact that since all three were transmitted together, Eser Neti'os applies only during the times of the Beis ha'Mikdash. Rather, the Gemara is merely pointing out that since we find a Halachah l'Moshe mi'Sinai that applies only during the times of the Beis ha'Mikdash, it makes sense that the Halachah l'Moshe mi'Sinai of Eser Neti'os also applies only during the times of the Beis ha'Mikdash.)