A sense of self – Bo
The regular view is that Aaron was the speaker and Moses was the man of action.
However, Reb Shmuel Mohilever said that there was a double task to be performed. One leader was needed to take the people out of Egypt; the second was there to take Egypt out of the people.
The Hebrews were there so long that they had become immersed in Egyptian ways. Despite the bitterness of the enslavement the Hebrew community had got used to Egyptian customs (including Egyptian speech, clothing and names) and needed to regain their self-respect, self-confidence and self-identity.
They needed to regain a clear and unambiguous sense of self.