You will not only be a god vis-à-vis your brother Aaron (iv 16)—that is, you will instruct him what to say, just as God instructs His prophets—but I have also made you a god before Pharaoh. Although Pharaoh is himself considered a deity, he is nevertheless accustomed to hear the prophets of Egypt address him in the name of their gods; now you will appear before him as one of the divinities, who do not speak directly but through their prophets, and Aaron your brother shall be your prophet, and he will speak in your name to Pharaoh. These words possibly contain a bitter ironic reflection on the Egyptian deities who ‘have a mouth yet do not speak.’
But you, Moses, will transcend the gods of Egypt in that you will not be wholly dumb: You shall speak all that I command you—words few in number but decisive in content you will be able to speak, and you will utter them at My command. . . . (Umberto Moshe David Cassuto, A Commentary on the Book of Exodus [trans. Israel Abrahams; Varda Books, 2005], 89)