Chazal tell us that the expression "na'aseh v'nishma" was used only by angels in their service of Hashem until the Jewish people came used it to declare their commitment before matan Torah. What is so special about these two words? If the phrase is simply an expression of unquestioning loyalty, would we expect less from the Jewish people after they merited yetziyas mitzrayim and a blatant display of hashgacha along the journey to Sinai? It would be surprising if Bnei Yisrael were not willing to accept the Torah willingly, even sight unseen! It must be that there is something more here…
The Rishonim (see Tosfos, Brachos 11, Rosh) ask why a person does not have to make a new birchas haTorah if he takes a break from learning during the day. Why is learning Torah different than, for example, the mitzvah of sukkah, where a person would be required to recite a new bracha if he leaves the sukkah and then returns later? The Beis Yosef (O.C. 47) cites an answer offered by the Agur. Even if a person stops learning to do other mitzvos, those mitzvos have halachos and dinim that govern how they are performed. There is never really a hefsek, a break from learning Torah, as every mitzvah act must involve Torah thoughts about what to do and how to do it and when and where to act. [The Emek Bracha quotes the Agur as I explained it here, in connection with mitzvos, but as cited by the Beis Yosef the Agur actually says even more: every act, even going to the restroom, is governed by halachos, and therefore there is never a hefsek from Torah.)
The Bikkurei Ya'akov paskens that birchas haTorah should be recited before performing the mitzvah of netilas lulav if one takes the lulav before davening. Rav Shternbruch (Moadim u'Zmanim vol 8) wonders why this should be so -- what does the bracha on talmud Torah have to do with the mitzvah of lulav? In light of the Agur, there is no question. Netilas lulav, like other mitzvos, has a myriad of halachos that define how it should be performed. One cannot engage in the proper performance of the mitzvah without also engaging in Torah thought. (Perhaps the Agur holds that even hirhur of Torah requires a bracha.)
I think that "na'aseh v'nishma" points to this link between deed, “na’aseh,” and Torah study, “nishma.” Judaism does not consist of two separate realms, the practical and the intellectual, but rather the practical itself must be an intellectual experience. "Na'aseh v''nishma" does not mean we will do and then study, a sequential relationship between ideas. Rather it means that through doing we will arrive at study, a logical relationship. "Na'aseh v'nishma" is not a "hakkava shichnit," to use the Rogatchover's jargon, i.e. a commitment to two mutually exclusive ideals that exist side by side, but rather "na'aseh v'nishma" is a a commitment to a synthesis, a "harkava mizgit," a hybrid fusion.
Chazal tell us that myriads of angels descended to place two crowns on the head of every Jew, one for the commitment to "na'aseh", one for the commitment to "nishma". After the cheit ha'eigel, the angels returned to reclaim those crowns. Why, asks the Avnei Nezer (cited by the Shem m'Shmuel), should the angels have reclaimed the crown of nishma? The commitment of "na'aseh" may have been undermined by the act of worshiping the eigel, but how was the commitment to "nishma," to learning, affected?
The removal of both crowns underscores that learning and mitzvah performance are intertwined. Torah study without a commitment to practical implementation is worthless; practical implementation without Torah knowledge is impossible.
It is uniquely human to take action and afterward exclaim, “What was I thinking!?” but angels have no such second thoughts – deed and thought are united as one. This is the ideal of “na’aseh v’nishma” which we experienced at Sinai.