It is hard to understand the way Moshe and Aharon presented their demands of Paroh, demands which resulted in the freeing of Bnei Yisrael from bondage and their exodus from Egypt. Hashem told them to tell Paroh that they want to travel for three days into the desert and bring sacrifices to Hashem (Shemot 5:3). Was there a need for Hashem to hide the fact that they were to be leaving permanently and not just bringing sacrifices and returning? Certainly Hashem was capable of getting Paroh to agree to anything. In fact, he even had to harden Paroh’s heart so that he would not agree earlier.