Shevuos

The phrase 'naase v'nishma' and its sequence which places 'naase'- doing- before 'nishma'- hearing, originates with the Malachei Hashareis. It could be said only by them, for it expresses the fact that hearing is not essential to angels, nor is it what brings them to do the will of Hashem. Malachim have no free will, they have no reality except to do the will of Hashem. Obviously, they must hear if they are to know what they are to do, but their actual doing needs no causes. Their very name identifies them- malach means messenger - they have no existence except to be sent and to serve. 'No malach can be sent on more then one mission' because their mission becomes their essence, and they cannot have more than one essence. Precisely because all reality for malachim is in their doing- they are beings that do, naase must precede nishma.
And this became the precise nature and character of the new creation which emerged at Sinai. From the moment of Matan Torah there exists upon this earth a creation whose essential reality, whose entire existence, is to do the will of Hashem. The name of this creation is Klal Yisroel. Reb Yerucham Levovitz once said; "The greatest act of bechira is to choose to lose your bechira". When we proclaimed in unity 'naase v'nishma' we chose as a nation to become angel like, to have only one reality- to do the will of Hashem.
The supreme achievement of Matan Torah was not that heaven descended upon earth, the supreme achievement was the fusion of heaven and earth into one entity and the concerns of heaven are the only reality upon earth. Hashem, Yisroel and Torah became one. Hearing is no longer essential to Klal Yisroel, nor is it the cause for doing. Doing now comes because we are one with Hashem. And so Klal Yisroel also said 'naase' before 'nishma'- just like the Malachim.
(Pachad Yitzchok Shevuos Maamer 4:7- traslation from; Citadal And Tower I page 82)