Bearing in mind that all the Mitzvos were said at Sinai, what is the special connection between Sh'mitah and Har Sinai?
Rashi (citing the Sifra): To teach us that, just as the Sh'mitah was given at Sinai, its K'lalim, P'ratim and Dikdukim (its principles, details and fine points), so too, were all the Mitzvos given at Sinai with their K'lalim (the general rules), P'ratim (the details) and Dikdukim (the finer points). And we learn this from the fact that Sh'mitah is not repeated at Arvos Mo'av, (where most other Mitzvos are repeated). 1
Ramban and Seforno: When, in Mishpatim, Sh'mos 23:11, when Moshe was on Har Sinai, the Torah wrote "ve'ha'Shevi'is Tishm'tenah u'Netashtah, ve'Ichlu Evyonei Amecha", it did not include the details of Shevi'is. So it mentions "be'Har Sinai" here ? even though it is being said in the era of the Ohel Mo'ed ? to teach us that the P'ratim and the Dikhukim that it is about to teach were all said to Moshe at Sinai as well. 2
Rashbam: It teaches us that Sh'mitah was said at Har Sinai, before the Ohel Mo'ed was erected.
Hadar Zekenim, Da'as Zekenim and Rosh #1 (in Pasuk 20): All of Seifer Vayikra until now was said in the Ohel Mo'ed and pertains to the Ohel - Mo'ed. Korbanos, Metzora, Temei'im, Kehunah? However, B'har and Bechukosai discuss Sh'mitah, Yovel, Erchin and Cherem, which are not so relevant to the Mishkan and Kehunah. It is nevertheless not inappropriate to insert them in Seifer Vayikra (Toras Kohanim), since the Kohanim are connected to Charamin and Erchin; they blow the Shofar in the Yovel, 3 and fix the years 4 (Sh'mitah and Yovel). And the Torah writes "be'Har Sinai", because, as opposed to the previous Parshiyos, they have no relevancce to the Ohel Mo'ed.
Rosh #2: In the first Dibros - the first forty days on Har Sinai, Moshe was commanded on the Mishkan, Korbanos and Sh'mitah. Once they sinned [with the Eigel], Moshe thought that all the previous commands are negated, and he broke the Luchos, When Hashem pardoned Yisrael, Moshe himself reasoned that the Mitzvos apply, and he commanded us about the Mishkan and Korbanos, and then he returned to teach about Sh'mitah, which was commanded on Sinai.
Moshav Zekenim (citing R. Eliezer of Garmaiza): It mentions Sinai because the Parshah conttains Yovel. Yovel is the fiftieth year, and Matan Torah was in the third year from the end the fiftieth cycle since the creation of the world - which ended in 2450, (according to the opinion that the fiftieth year is the first year of the next Yovel). According to the opinion that the fifty-first year begins the next cycle, the forty-eighth Yovel ended in year 2400, and Matan Torah was at the end (the 48th year) of the forty-ninth Yovel.
Ba'al ha'Turim: The Torah actually juxtaposes Sh'mitah to the Mekalel (the man who cursed Hashem) because it was on Har Sinai that they heard "Lo Sisa!" ? at which point the entire mountain shook. 5
See Ramban, who queries this explanation, based on the fact that there are many other Mitzvos that are not mentioned there.
Ramban, citing the Sifra: And we learn all the other Mitzvos from Sh'mitah from the last Pasuk in Bechukosai, where, following the Mitzvos of Sh'mitah and Yovel, the Torah concludes "Eileh ha'Mitzvos asher Tzivah Hashem ... be'Har Sinai". See Ramban DH 've'Chein Shanu'.
Hadar Zekenim, Da'as Zekenim and Rosh: As the Torah writes in Beha'aloscha Bamidbar, 10:8 "u'Venei Aharon ha'Kohanim Yiske'u ba'Chatztatzros".
I do not know the source that Kohanim fix the years - unless we say that S'tam Chachamim are Kohanim. See Devarim 17:12 (PF).
See Ba'al ha'Turim, who elaborates further.
Why does the Torah insert the Mitzvah of Sh'mitah here?
Ramban #1 (citing the Ibn Ezra): This is part of the covenant with Yisrael - Sh'mos 24:7. 1 It is taught here to connect it with sins that are subject to Galus - the Arayos, in Acharei-Mos and Kedoshim, and letting the land rest in Sh'mitah. 2
Ramban #2: Har Sinai in this Pasuk is referring to the second time that Moshe ascended the Mountain to receive the second Luchos, and that is when Hashem taught him about the Sh'mitah. 3
Seforno: Seeing as they were about to enter Eretz Yisrael, 4 Hashem taught them about Sh'mitah, particularly about the Dinim pertaining to the land, to ensure that they would not be exiled from it. 5
Moshav Zekenim #1 (citing R. Yehudah ha'Chasid): It is placed next to the Mekalel (the blasphemer) a. because modest Chachamim teach their Talmidim Hashem's name once in Sh'mitah (a cycle of seven years), b. because the blasphemer's Pasul lineage was taught, since one may not deposit fruit with someone suspected of transgressing Sh'mitah; 6 c. because if one will ask from where did the blasphemer know Hashem's name, the answer is ? from Har Sinai.
Moshav Zekenim #2 (citing the Ri): After teaching Tzara'as of houses, which is confined to Eretz Yisrael, it teaches about Sh'mitah, which also appplies only in Eretz Yisrael. 7
Moshav Zekenim #3 (in Pasuk 3): It is placed next to stoning [the blasphemer], to hint that one may not clear stones from his field into the R'shus ha'Rabim (a public domain) - and in Sh'mitah, all fields become Hefker, like a R'shus ha'Rabim. 8
Ramban: When they declared "Na'aseh ve'Nishma".
Ramban: See 18:28, 26:34. And the Torah inserted Emor first, in order to mention the Shabbasos before the Sh'mitah. .
Ramban: Immediately following the erection of the Mishkan, Hashem called Moshe (Vayikra, 1:1) and commanded him the Parshah of Korbanos and all of Toras Kohanim (Vayikra), which Moshe immediately taught to Yisrael. He also told them that Hashem had commanded him on Har Sinai to explain to them the Sh'mitah and Yovel, and to enter into a (new) covenant with them on all the Mitzvos and Mishpatim with a curse and an oath. This covenant did not require the Korbanos that the first one did; they did however, reaccept the original covenant with the oaths and the curses (mentioned in Bechukosai - see 26:46), because Hashem pardoned them (for the sin of the Eigel) on these conditions, as the Ramban explained in Vayakhel, Sh'mos, 34:47. In fact, Yisrael reaffirmed the B'ris again under the same conditions at Arvos Mo'av (See Devarim 28:69). Moshav Zekenim ? the entire time they were building the Mishkan, Moshe did not interrupt them to teach them new laws, until they finished and erected the Mishkan. See also Oznayim la'Torah DH 'be'Har Sinao #5, for a similar detailed overview of all the Parshiyos following Matan Torah until the end of Bechukosai.
Seforno: As the Pasuk testifies in Bamidbar 10:29.
Seforno: Since the punishment for Sh'mitah is Galus, as the Pasuk states in Bechukosai, 26:34 and in Divrei Hayamim 2, 36:21.
What is the connection between Pasul lineage and being suspected about Sh'mitah? (PF)
Why were Acharei Mos, Kedoshim and Emor taught in between? He implies that it is because they were taught in the Ohel Mo'ed, like the first half of Vayikra, whereas B'har and Bechukosai were taught in Arvos Mo'av.
Moshav Zekenim: The Gemara in Bava Kama 50b cites a case where somebody cleared stones from his field into the R'shus ha'Rabim, and when someone rebuked him for throwing the stones from a domain that did not belong to him to a domain that did, he mocked him. However, when he subsequently sold his field, and walking in th street, he stumbled over thos same stones, he realized how right that man had been, how he had indeed cleared the stones from a place that was (now) not his to a place that was his.
Rashi citing the Sifra, states that, like Sh'mitah was given at Sinai, so too, were its K'lalim, P'ratim and Dikdukim. How do we know this?
Rashi: Because, since they were not repeated at Arvos Mo'av (in Seifer Devarim), they must have all been given at Sinai. 1
Ramban: Because 'K'lalosehah' refers to "veha'Shevi'is Tishmetenah u'Netashtah" in Mishpatim Sh'mos, 23:11; P'ratosehah and Dikdukehah are taught here, and "Eileh ha'Mitzvos... " in 27:34 compares all the Mitzvos to Sh'mitah. 2
Moshav Zekenim: The words "be'Har Sinai" are superfluous - to teach us that all Mitzvos were taught in their entirety at Har Sinai.
