In Parashat Yitro, in the preparations for receiving the Torah, we are told that Moshe came to the people and they all said, “All that God has said – we shall do” (19:8). In parashat Mishpatim, as they are about to enter into the covenant of the basins, we are told: “He took the Book of the Covenant and read it to the people, and all the people said: All that God has spoken – we shall do and we shall obey” (24:7).
We may ask what happened in between, and what brought about such a revolutionary change in such a short time that Bnei Yisrael were able to declare, “Na’aseh ve-nishma," rather than merely promising, “Na’aseh”?
What was added in Mishpatim, and what facilitated the transition from “na’aseh” to “na’aseh ve-nishma,” was threefold: first, the purely religious aspect of the revelation at Sinai, including its experiential and personal dimension; second – and no less important – the involvement in study and the deepening knowledge of Torah; and third, Torah experience and knowledge implemented on both the personal and societal levels.
[Based on a Sicha by Harav Aharon Lichtenstein (summarized by Shaul Barth with Reuven Ziegler and translated by Kaeren Fish)]