What is the significance of the juxtaposition of "Re'u Ki Hashem Nasan Lachem Es ha'Shabbos," to the previous Pasuk, "Lishmor Mitzvosai v'Sorosai"?
Yerushalmi Nedarim, 3:9: It teaches us that Shabbos is equal to all the Mitzvos in the Torah. 1
See Torah Temimah, note 43.
Why did Moshe say to the people "Re'u!"? What were they supposed to see?
Rashi: The fact that a double portion of Manna fell on Friday served as visual evidence that Hashem had sanctified the Shabbos and that they were not supposed to collect Manna on it.
Seforno: "Re'u" means (not 'See', but) 'Reflect' - that Shabbos is not just a Mitzvah, but a unique gift that Hashem gave to you exclusively. 1
Seforno: As the Gemara states in Shabbos (6b), and as we say in the Shabbos Amidah, 'And He did not give it to the nations of the world...' 'And Bnei Yisrael will keep the Shabbos, to make the Shabbos for all generations... in order to attain a day that is entirely Shabbos - Olam ha'Ba (Tamid 33b).
What are the connotations of the word "[Shevu Ish] Tachtav"? What was Moshe telling Yisrael?
Rashi #1: Tachtav" means four Amos in all directions. 1 The Chachamim used this Pasuk to support the Din that allows someone who has already left the Techum Shabbos to move up to four Amos from where he is standing. 2
Targum Yonasan: He was teaching the prohibition of carrying from one major domain to the other, and of carrying four Amos in a public domain. 3
What did Moshe mean when he said, "Al Yeitzei Ish mi'Mekomo ba'Yom ha'Shevi'i"?
Rashi #1 and Targum Yonasan: It hints at the Din d'Rabanan prohibiting traveling beyond the Techum of two thousand Amos on Shabbos. 1
Rashi #2: Basically, Moshe was ordering them to remain in the camp and not to go out to collect the Manna on Shabbos.
Rashi (in the Beraisa of R. Yishmael): This is an example of 'Davar ha'Lameid mi'Inyano.' Seeing as the Parshah is talking about the Manna, which they had to travel two thousand Amos to collect, the Pasuk is issuing a prohibition against traveling more than two thousand Amos on Shabbos. 2
Rashi, ibid.: As opposed to the preceding Halacha, against moving from one's current location four Amos. See Gur Aryeh below.
The Gemara in Eruvin 17b, learns from here that someone who travels outside the Techum on Shabbos is subject to Malkos, and the Chachamim argue over whether this applies to the Techum of two thousand Amos, or to that of twelve Mil (and two thousand Amos is only Asur mid'Rabanan). See Torah Temimah, note 45. See Torah Temimah, citing Eruvin 51a, which learns the Techum of two thousand Amos from a series of Gezeiros Shavos from Pesukim in Mishpatim and Mas'ei (also see ibid. note 47, and see Gur Aryeh below).
Why does the Torah write "Hashem Nasan Lachem Es ha'Shabbos" (in the past tense)?
Moshav Zekenim (to 5:4): When Moshe was in Pharaoh's house, Moshe convinced him that slaves will work better if they have a day of rest. Pharaoh allowed Yisrael to choose a day, and Hashem put into their heads to choose Shabbos. 1
Also see Oznayim la'Torah to Shemos 2:11. (But were there not Tzadikim who had a tradition of Shabbos from the Avos?! Even if they needed to work, they could avoid Melachos on Shabbos as much as possible? Moreover, the tribe of Levi did not have to work - refer to 5:4:2:1 ? (PF).)
QUESTIONS ON RASHI
Rashi writes: "See - with your own eyes, that Hashem in His Honor is commanding you regarding the Shabbos." Why does Rashi emphasize this?
Gur Aryeh: The term "see" is extra here; the Pasuk could have sufficed by saying, "Hashem has given you the Shabbos." Seeing is more than merely hearing. 1
What Bnei Yisrael were supposed to see, was the clear miracle that Hashem doubled their Manna on every Erev Shabbos - as Rashi continues.
Rashi writes: "See with your own eyes, that Hashem in His Honor is commanding you regarding the Shabbos; for behold the miracle that happens every Erev Shabbos - to give you bread for two days." Mizrachi asks - Why does the double portion of Yom Shishi prove that there is Shabbos; on the contrary - perhaps it proves that Yom Shishi is a sanctified day! It would have been clearer to point to a different miracle - that no Manna fell on Shabbos itself!
Mizrachi: Indeed, the main idea here is that no Manna would descend on Shabbos (of which the double portion on Yom Shishi was a direct corollary). The Torah only points to the double portion, because something that exists and we can point to, serves as better proof than when something is missing.
Gur Aryeh: We did not need any proof that the seventh day is a sanctified day in the abstract; the Bnei Yisrael knew and understood this already. What we did need to learn, is that this fact was relevant to us! Hashem said, "See that Hashem has given you the Shabbos" - He wants you to be the ones to observe and safeguard the Shabbos by abstaining from Melachah. Had Shabbos not been relevant to Yisrael, why should Yom Shishi provide them a double portion, only because they would be lacking food the next day? Every other weekday provided Manna for that day only! It must be because Bnei Yisrael would be forbidden to perform the Melachos of gathering and cooking on Shabbos, and Hashem wanted that they should prepare everything beforehand. 1
In other words, had Yisrael not been commanded to observe Hashem's Shabbos, the fact that no Manna fell on Shabbos would have nothing to do with Yisrael per se. We might have said that the sanctity of Shabbos itself simply causes certain phenomena to cease on Shabbos. (As a parallel, the river Sabatyon does not throw rocks on Shabbos, and that is its nature ever since Creation - see Sanhedrin 65b. (CS)) Yet had that been the case, we would not have received a double portion of Manna beforehand; as the Manna's basic rule was that it consisted of that day's Parnasah, and no more. Rather, there must have been a positive reason for receiving a double portion - namely, because Hashem gave the Shabbos to Yisrael, and He required that we prepare for Shabbos beforehand.
Rashi writes: "'Each man must dwell in his spot (Tachtav)' - From here, the Sages drew support [for the concept of] four Amos for someone who has left his Techum .... 'Let no man leave his place (Mekomo)' - These are the 2000 Amos of Techum Shabbos." Why interpret this way?
Gur Aryeh: A person's Techum of 2000 Amos is his "Makom;" anyone who is still within his Makom is commanded not to leave it. The first phrase must be addressing someone who no longer has a "Makom," because he has already left it; he must remain "Tachtav," i.e. within 4 Amos. 1
Eruvin 48a: Three Amos for one's Guf, and one additional Amah to stretch out his hands and legs.
Rashi writes: "'Let no man leave his place' (Al Yetzei Ish mi'Mekomo) - These are the 2000 Amos of Techum Shabbos." How is this number derived?
Gur Aryeh (from Eruvin 51a): [In a different context,] the Torah delineates the surrounding spaces around the [Levite] cities of refuge, as 2000 Amos in each direction (see Bamidbar 35:5). 1
Gur Aryeh adds another hint. The word "Yetzei" (in our Pasuk) is spelled Yud-Tzadi -Alef; the Gematriya value of these three letters is a. 10; b. 90; c. 1. The sum of the products of all possible two-letter sequences from this word (ab + ba + bc + cb + ac + ca), gives us 1800 + 180 + 20 -- a sum total of 2000.