The angels' secret
When the Israelites gave precedence to 'we will do' over 'we will listen,' a Heavenly Voice went forth and called out: "Who revealed to My children this secret, which is employed by the Ministering Angels, as it is written, "Bless the Lord, His angels. Your who are mighty in strength fulfil his word, to listen to the voice of his word. First they fulfil and then they listen."Rashi explains that they are ready to fullfil even before they hear.
My gradnfather say that the matter here needs some elucidation. Why is this called the raz [secret] of the angels that arouses astonishment in the exclamation of "Who revealed to My children this secret?" Isn't it logical that the smaller one would do waht the greater one commands even if he doesn't understand, all the more so when the command comes from Hakodesh Baruch Hu?
What Bnay Yisrarel revealed here in saying they will do before they will listen is that they recognized not just the need to accept the commandments but that the only way they could understand them is by accepting them only through fulfilling them. That's the secret of the ministering angels. It corresponds to what Chazal say (Avos 3:17) "If there is no fear, there is no wisom." Likewise in evamos 109b kol sheyeshno beasiya yeshno belemida, kol she'eyno beasiya eyno belemida"
Related post http://kallahmagazine.blogspot.com/2015/10/dvar-yehudah-parsha-points-from-my.html