(From Rabbi Levi Yitzhak of Berdichev’s Kedushat Levi)
The Torah Should be Accepted through a Personal Decision, “Not in order to receive a reward.”
…That is why Israel was not given the Torah immediately after the splitting of the Red Sea, because if they had received it after the splitting of the Red Sea, it would have looked as if they accepted the Torah in order to receive a reward, as a result of the great miracles that had just been performed for them. That is why God waited a bit – meanwhile they could partially forget the miracles performed for them, as it says, there was no water for the community, and they complained. Afterwards, they received the Torah, saying that they would do it and hear it, which proves that they accepted the Torah solely out of love for the Torah.