What is the definition of "Aron"?
Rashi: An Aron is a sort of box that stands on its base - and not on legs.
Why, by all the Keilim, does the Torah write "ve'Asisa", but by the Aron "ve'Asu"?
Ramban #1: Because "ve'Asisa" refers to Moshe, and Moshe corresponds to all of K'lal Yisrael. 1
Ramban #2, Da'as Zekenim and Hadar Zekenim (all citing the Midrash Rabah): The Torah deliberately uses the plural here, to give everybody the opportunity of gaining a portion in the Torah by helping Betzalel, by donating a golden vessel towards the Aron, or by assisting him even a little or even with the mere intention of participating. 2
Which also explains why, in connection with the Aron itself, the Torah (from Pasuk 11 and onwards) switches to the second person "ve'Tzipisa" "ve'Asisa" ... (Ramban).
Hadar Zekenim Moshav Zekenim and Da'as Zekeinim: All the more so, everyone is obligated to honor Chachamim (and do their work for them - Da'as Zekenim). Reward, punishment and toil in Torah do not apply to the Aron, [yet we must honor it], and all the more so Chachamim!
How will we reconcile this Pasuk ("Ve'asu Aron Eitz") with the Pasuk in Eikev "Ve'asisa l'cha Aron Eitz"?
Yoma, 3b: When Yisrael are doing the will of Hashem, the Aron is ascribed to their merit; when they are not, it is ascribed to the merit of Moshe. 1
Yoma, 72b: It is a hint that that the residents of a town ("Ve'asu") are obligated to do the work of a Talmid-Chacham ("Ve'asisa"). 2
Ba'al ha'Turim (citing the Beraisa of Meleches ha'Mishkan): Because Sh'lomoh ha'Melech made a replica of all the Keilim except for the Aron
What size Amos were used to measure the Keilim?
Yerushalmi Shekalim, 6:1: They were measured by Amos of six Tefachim, 1 in which case the Aron measured fifteen by nine Tefachim, and was nine Tefachim tall.
See Torah Temimah, note 14. See also Oznayim la'Torah, who refers briefly to the Machlokes Tana'im in Bava Basra as to whether the measurements of the Keilim were in Amos of six Tefachim or five Tefachim, and to a few other details.
Seeing as Betzal'el constructed the Mishkan before the Keilim (See Sh'mos 36:8), why does the Torah here place the Keilim first?
Rashi: Refer to 38:22:1:1 and note, and to 38:22:151:1.
Rashbam: Because the entire Mishkan was built only in order to house the Aron. 1
Oznayim la'Torah: Even though the main practical function of the Mishkan was the Avodah that was performed on the Mizbe'ach ha'Olah, its main purpose was to house the Aron (the first and most important of the Keilim) with the Torah 2 - in the holiest section of the Mishkan - to safeguard against those who, over the ages, would attempt to make changes in the Divine text, 3 and to demonstrate that, without the Torah, the Avodah is insignificant. 4
As we say in 'L'chah Dodi' 'Sof Ma'aseh be'Machshavah Techilah'.
Oznayim la'Torah: The most important of the three pillars in which the world stands. Refer to 25:5:2:3***.
Even though they did not actually Lein from it. See Oznayim la'Torah, who elaborates further.
See Oznayim la'Torah on Pasuk 16.
Is the thickness of the walls included in the dimensions of the Aron?
Moshav Zekenim (citing Bava Basra 14a): The dimentions of the Aron include the thickness of the walls. 1 However, if so, bearing in mind the Gemara in Sukah 4b, which states that the outer wall was level with the Kapores which rose one Tefach above the Aron itself, the Aron will have been more than one and a half Amos tall. We must therefore say that the Torah gave the Shi'ur of the Aron including the thickness of the middle Aron (but not of the outer one). 2
