Why does the Torah write "Vayis'u me'Har Hashem" and not '... me'Har ha'Elokim' or 'me'Har Choreiv' as in other places?
Shabbos 116a: To teach us that when Yisrael left Har Sinai, they turned away from Hashem. 1
Targum Onkelos and Targum Yonasan: It was the mountain on which Hashem revealed His Glory (the Shechinah).
What is the meaning of "Derech Sheloshes Yamim"?
Rashi #1: It means that they traveled three days' journey in one day - in order to hasten their entry into Eretz Cana'an.
Rashi #2: Refer to Devarim, 1:2:1:1.
Ramban and Rashbam: The Torah is simply informing us that they traveled for three days straight without a break, 1 and that, during those three days the Cloud traveled in front of them followed by the Aron. 2
Seforno: This is the distance from Har Sinai to Eretz Yisrael - since in three journeys 3 they went from Midbar Sinai until opposite Kadeish Barne'a in Midbar Paran, from where they sent the spies. 4
Rashbam: Which explains why they were travel-weary and why they complained. See beginning of chapter 11. Da'as Zekenim ? at night, the Cloud rested on the Aron. They could not travel three days and nights straight, since one cannot go that long without sleeping. In the morning, the Aron left the camp and the Levi'im prepared to travel before the Machanos.
Da'as Zekenim: As if it had said 'ba'Derech Sheloshes Yamim' - similar to "Ki Sheishes Yamim Asah Hashem?" - Ki Sisa Sh'mos, 31:18 - as if it had said 'be'Sheshes Yamim ... '.
Seforno: Kivros ha'Ta'avah, Chatzeros and Rismah (alias Kadeish Barne'a - See 33:18).
Seforno (on Pasuk 11): Since Kadeish Barne'a was the first town of Eretz Yisrael at which they arrived (See Devarim, 1:19 -22).
What is the significance of the three days mentioned in connection with the Aron?
Rashi: The Aron traveled ahead of Yisrael to prepare the route for them. 1
Ramban: Refer to 10:33:2:2.
Why was the Aron traveling ahead and not together with the B'nei K'has?
Rashi: The Aron mentioned here is not the Aron that was housed in the Kodesh Kodshim, but the Aron that accompanied them when they went to war, which housed the broken Luchos. 1
Ramban and Seforno: Although in principle, the Aron was carried by the B'nei K'has, on this occasion where they traveled (these three journeys - Seforno) through the great and terrifying desert, it traveled by itself ahead of them 2 to secure a suitable camping spot on their behalf. 3
Refer to Devarim, 10:1:2:1 & 2 and notes, regarding the Machlokes between Rashi and the Ramban in connecion with the wooden Aron that Moshe made. Refer also to 10:33:153:1 & 2.
Seforno: This explains why, in the next Pasuk, the Torah writes that the Cloud hovered above them when they traveled - and did not go in front of them like it did on all other occasions.
See also Rashbam, who explains that the Cloud traveled above the Aron.
How far was the Aron from B'nei Yisrael?
Moshav Zekenim citing R. Yehudah ha'Chasid: It was two thousand Amos away, like we find in Yehoshua (3:4).
Rashi says that a different Aron was taken to war, and it housed the broken Luchos. But the Gemara says in Bava Basra 14b that the whole and broken Luchos were placed in the same Aron?
Abarvenel: Rashi holds like the opinion in the Yerushalmi Shekalim, 8:3 that there were two Aronos, whereas the Gemara in Bava Basra holds like the opinion there that there was only one Aron. 1
Da'as Zekenim, Hadar Zekenim and Rosh (in Devarim 10:1 & 10:2): The Gemara in Bava Basra is discussing the era of the Beis-Hamikdash, which was the permanent Menuchah, whereas Rashi is discussing the period before the Beis-Hamikdash was built.
Refer to Sh'mos 25:12:151:2*. See Sifsei Chachamim
QUESTIONS ON RASHI
Rashi writes that they traveled three days' journey in one day. But the Gemara in Ta'anis 29a, when counting the days from when they left Har Sinai until sending the Meraglim, counts them as three days? (Moshav Zekenim)
