The Torah commands us to count the Omer so we can relive the Exodus from Egypt. Just as the Jews back then anxiously anticipated the great day when they were to receive the Torah, so too we count the days till Shavuos, the holiday that commemorates the giving of the Torah. To the Jews then, accepting the Torah on Mt. Sinai was even greater than their redemption from slavery. So we count each day to bring ourselves to that sense of great enthusiasm of, “When will that day come?”
The difficulty with this Sefer Hachinuch is the statement that “to the Jews then, receiving of the Torah was even greater than being freed from slavery.” This seems difficult to understand when we envision what it was like to be a slave in Mitzraim. – By Rabbi Benzion Shafier