The Gemara (Shabbos 88a) compares Am Yisrael saying "Na'aseh" before "Nishma," to a Tapuach tree, "... which gives its fruit before its leaves." Rabbeinu Tam (Tosfos DH Piryo) says this refers to an Esrog tree, on which last year's fruit remains and precedes this year's leaves. But why is this so special? Why is the Esrog comparable to our having said "Na'aseh v'Nishma"?

In Shemos 19:8 (which we read on Shavuos), "the entire people answered together in unison, "Na'aseh!" ("We will do!"; also see 24:3). But strikingly, in this Pasuk of "Na'aseh v'Nishma," there no mention of unity!

What was the "Sefer ha'Bris," in response to which Bnei Yisrael exclaimed "Na'aseh v'Nishma"?

On what date did the events in this section (Shemos 24) take place?