On the famous pasuk of "na'aseh v'nishma" -- "we will do and we will listen!" (Shemot 24:7), the Gemara in Masechet Shabbat (88a) comments:

At the moment that Yisrael preceded "we will do" to "we will listen," a heavenly voice rang out and said to them, "Who revealed to my children this secret that the angels use, as it says, "Bless Hashem, O His angels; the strong warriors who do his bidding, to listen to the voice of his word." First -- "who do," and afterwards -- "to listen."

Rav Kook zt"l writes about this in his book, "Orot Hatorah" (ch. 8):

Preceding "na'aseh" to "nishma" indicates an appreciation of the Torah because of its Divine quality, in addition to the appreciation that it deserves because of the pragmatic value in learning it. Since they already said, "we will do," the link to the value of pragmatic learning is already implicit, so that "we will listen" indicates the link to its inherent, qualitative, value.

What Rav Kook wrote in a few, brief words, the "Beit Halevi" explains at length in the introduction to his book, which can help us understand Rav Kook's comment. In the Zohar it says, "na'aseh" -- with acts of Torah; "nishma" -- with words of Torah. In other words, "na'aseh" refers to observance and "nishma" refers to learning. There are two fundamentals in Talmud Torah:

Learning as a means to know how to observe the mitzvot, as it says in Pirkei Avot, "An am ha'aretz (unlearned person) cannot be a chasid."

Learning as an end in and of itself, which is a unique quality of the Torah.

Women, for example, are not obligated in Talmud Torah, yet they make Birchot Hatorah, since they are obligated to learn the halachot that they are commanded in. In contrast, men are obligated in Talmud Torah even regarding those mitzvot that they are not obligated in.

With this, the "Beit Halevi" explains the dispute between R. Yishmael and his nephew, who asked him, "Someone like myself, who already learned the entire Torah -- can I learn Aristotelian Philosophy?" R. Yishmael responded, "It says, "You should contemplate it day and night.' Go and find a time that it neither day nor night!" R. Yishmael's nephew thought that the mitzvah of Talmud Torah is merely a means to knowing it, and since he already knew the entire Torah, it was possible for him to learn other things. R. Yishmael answered him that besides learning Torah as a means to observance, there is an inherent purpose in learning Torah, and therefore a person is obligated to learn Torah even if he thinks that he learned and knows it all.

This is why there is special significance to preceding "na'aseh" to "nishma," and this is also the intention of Rav Kook zt"l. When Bnei Yisrael said, "we will do," they certainly accepted also to listen before doing, since it is impossible to do without learning first how to observe. Therefore, when they said "na'aseh," it is as if they already said implicitly, "we will listen [i.e., learn for the purpose of observance] and we will do." When they said again afterwards, "nishma," they clearly were referring to that aspect of learning that is already after knowing, due to the special quality of the Torah, and not due to its pragmatic value.

This is the secret that the angels use, which has no parallel in this world, that a person should learn something as an end in and of itself, and not as a means to something else. Bnei Yisrael discovered what the angels knew of the special quality of the Torah!