Why was Yisrael's reaction to the Voice of Hashem so praiseworthy?
Rashi (in Avodah Zarah, 4b): 'They were strong and powerful in their of G-d.
Ramban (citing Berachos, 33b): 'Ha'Kol bi'Yedei Shamayim Chutz mi'Yir'as Shamayim.' Everything is in the Hands of Hashem with the ssole exception of Yir'as Shamayim. 1
Ramban: Yir'as Shamayim is in the hands of the people, and Hashem was expressing the hope that Yisrael would retain the level of Yir'as Shamayim that they had reached then (like a father wishes only what is good for his son