According to the popular Midrash, Bnei Yisrael had fallen to the 49th level of "tumah" (spiritual impurity) in Egypt. However, there appears to be no foundation for this criticism in either Parshat Shmot or Va'eyra. What is the basis for this harsh condemnation? By exploring the verses serving as the biblical source for this Midrashic censure, we can enhance our understanding of several difficult psukim in Parshat Va'eyra, and also arrive at a better perception of the nature of Moshe Rabeinu's "shlichut" (mission) to take Bnei Yisrael out of Egypt.