The first Keli (vessel) that Hashem commands Moshe to build is the Aron. A cursory analysis of the construction of the Aron would lead one to conclude that because of the Aron’s importance in that it held the Luchot, and possibly the Seifer Torah that Moshe wrote, it was built first. Such a conclusion is definitely correct, but there is something much deeper to the essence of the Aron. The Ramban points out that in reference to the Aron the Torah uses the word, “VeAsu,” “And you shall construct,” in the plural, as opposed to the other Keilim and even the Badim (the poles with which the Aron was held) and the Zeir Zahav (the golden crown surrounding the Aron) which the Torah describes using the words “VeYatzakta,” “VeTzipita,” and “VeAsita,” respectively, all in the singular. He explains that this distinction and specific emphasis on the pluralistic construction of the Aron alludes to the Mitzvah for every member of Klal Yisrael to participate in the building of the Aron. An individual who either donated gold for the sake of the Aron or helped Betzalel in its construction would merit the Torah. Apparently, there is a specific relationship that should exist between the individual and the Aron which will result in the acquisition of the Torah. How does that work? How does building the Aron help someone acquire the Torah?
The Torah requires that the Aron and Kaporet (the cover for the Aron) be made out of Zahav Tahor, pure gold, while the Badim and Zeir Zahav only require only “regularordinary” gold. The Meshech Chochmah explains that this is because the Aron and Kaporet are analogous to the Klaf of Tefillin, while the Badim and Zeir Zahav are similar to the Retzuot (straps) and Batim (compartments) of Tefilin. Just like the parchment must be tanned and treated “Lishmah” (with proper intent) and if they are not the Tefillin are Pasul, so too the Aron and Kaporet need to be made out of Zahav Tahor, pure gold, for the sake of the Aron. Conversely, the Badim and the Zeir Zahav only require only regular gold just like the Retzuot and Batim which Bedieved (ex post facto) do not needare not required to be made Lishmah. There is also a clear comparison between the Klaf, which is the Keli for the letters of the Torah, and the Aron, which is the Keli for the Luchot.
Expressing a similar idea, the Ramban (Hasagot LeSeifer HaMitzvot 33) writes that there is only a Mitzvah to have an Aron if there are Luchot which need to be stored. Thus, even if the Aron were to break, Klal Yisrael would be required to build another Aron exactly like the previous one. However, if there are no Luchot, such as during Bayit Sheini when the Luchot were hidden, there would no longer be a need for the Aron. The Maharal in the Gur Aryeh explains that this is because the nature of the Aron is a “Beit Kibul,” a receptacle, for the Eidut, namely, the Luchot. Thus, if there is no Eidut, there is no need for an Aron.
However, the Aron was not only the physical Keli for the Torah; its physical structure represented the nature of Torah. Rashi explains that the Aron was made out of three separate boxes: an Aron of gold on the outside, an Aron of wood inside of that, and another Aron of gold which fit inside the wooden Aron. Why couldn’t Betzalel build one Aron of wood and attach golden slabs to each side of the Aron? Why did there have to be three separate levels? The Maharal first explains that because the Aron had to be made out of wood with specific dimensions (2.5 Amah length by 1.5 Amah width by 1.5 Amah height), if Betzalel were to attach gold to each side he would violate the Issur of Bal Tosif (adding on to a command of the Torah) as the length, width, and height would be greater than those mandated by the Torah. However, he then goes proceeds on to explain that the Aron was made out of wood based on the Pasuk, “Eitz Chaim Hee LaMachazikim Bah,” “It is a tree of life to those who grasp it” (Mishlei 3:18). A tree constantly grows, just like Torah which is Klal Yisrael’s constantly growing connection with Hashem. However, Shelomo HaMelech also describes Torah as “Orech Yamim BiYminah UViSmolah Osher VeChavod,” “Long life in its right and in its left wealth and honor” (ibid. 16). Torah has a dual nature; on the one hand it is Orech Yamim while on the other hand it is Osher VeChavod. The Maharal explains that Orech Yamim, or Olam HaBa, is hidden while Osher VeChavod, honor and glory in this world, are in the openrevealed. And indeed the Aron expresses this idea. Just like Olam HaBa is concealed, so too the wooden Aron which represents the Torah/Olam HaBa is on the inside. However, just like Osher VeChavod, wealth and honor, can be seen, so too the golden compartments were on the outside and covered the wood on both sides.
Therefore, in order for Klal Yisrael to acquire the Torah, immediately after receiving the entire Torah the first task needed to be the building of a Keli to guard the Torah. However, because the Torah was not given just to Klal Yisrael in general but also to the individual in specific, each member of Klal Yisrael has a Mitzvah to participate in the building of the Aron, that is, a Keli for Torah. And because such a Mitzvah applies as long as there is a Torah that is needed to be stored, the Mitzvah should apply today as well. In order to acquire Torah one must make himself into a Keli that represents the nature of Torah. Parallel to the Aron, one must make himself into Zahav Tahor on the outside and Atzei Shitim on the inside. On the outside he must place himself in an environment that represents the Osher VeChavod of Torah. However, on the inside he must create a Keli that is constantly growing in Avodat Hashem and connection to Him, just like a tree constantly grows. Once he has fulfilled his obligation to make himself into a proper Keli worthy of guarding the Torah, he can truly acquire the Torah.