by HaRav Shaul Yisraeli zt"l
Hashem told Moshe and Aharon 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.
Perhaps the idea was not to use this approach as a way to get Paroh to agree but to teach a lesson. It was important that Bnei Yisrael should be liberated not just as an ethnic group of slaves being freed but that they were being freed as the Nation of Hashem. They also needed to know that Hashem is the one who runs His world. The idea was to break the Egyptian conception of how things are supposed to work. The Egyptian standard of success and their confidence in their civilization had to be broken. Their deities had to be slaughtered as sacrifices to the true G-d. They had to recognize that Hashem’s demands of them were just and that they were prepared to agree to His will. Even Paroh would have to acquiesce to the dictates of the King of kings.
Had Bnei Yisrael just asked for freedom from slavery, it is possible that Paroh would more easily have found the humanitarian appeal to have logic and merit. Maybe he would have found the moral basis to be gracious. Then there would not have been a theological element to the struggle between Bnei Yisrael and Egypt. It was specifically the theological basis of the conflict that needed to be the driving force in the emergence of the Nation of Israel. The world had to see that Paroh had given in to Hashem in this struggle.
Perhaps the above explains what Moshe meant when he said, amidst a bad start to his mission of freeing the nation: "From the time I came to speak in Your name, the situation for this nation has deteriorated" (Shemot 5:23). Moshe felt that the things he said, invoking Hashem, made things worse. Perhaps asking for freedom on humanitarian grounds would have been better. Paroh cannot accept, "Send My nation and they will serve Me," as this is a contradiction to what he presumed one would view as liberty.
Hashem answered Moshe: "With a strong hand, he will send them" (ibid. 6:1). It is not up to Paroh’s desires; he will be forced. Thus, the less the process of liberation makes sense, the more desirable it is.