출애굽기 4:15의 주석

AND I WILL BE WITH THY MOUTH. I.e., “to teach you that which you are to speak to Pharaoh.” G-d now told Moses that Aaron will speak on his behalf only to the people, as it is said, And he shall be thy spokesman unto the people,²⁸⁴Verse 16. but Moses himself was to speak to Pharaoh. It is possible that this was out of respect to the king. But in the end, Moses came back and said, Behold, I am of uncircumcised lips, and how shall Pharaoh hearken unto me?²⁸⁵Further, 6:30. G-d then permitted him that he should not speak even to Pharaoh. This [consent] was a distinction to Moses, and therefore He said there, See, I have set thee in G-d’s stead to Pharaoh, and Aaron thy brother shall be thy prophet.²⁸⁶Ibid., 7:1 And the intent of the expression [here in the verse], and I will be with his [Aaron’s] mouth,²⁸⁷I.e., why was this promise necessary since Aaron was not defective of speech? is that his words will find favor with everyone that will hear them.

ושמת את הדברים בפיו ואנכי אהיה עם פיך ועם פיהו, even though I could put all these words in his mouth this is not sufficient; it is necessary that I personally, assist both you and him to make sure that Pharaoh will absorb the words with his heart. Otherwise, he might deal with you from a position of autocratic arrogance and simply expel you from his presence.

ואנכי אהיה עם פיך, “and I shall be with your mouth, etc.” I shall give you precise instructions what to say to Pharaoh. At this point, G’d did not say that Aaron would speak on his behalf. Aaron would only speak on Moses’ behalf to the people, not to Pharaoh. We know this from verse 16 ודבר הוא אל העם, that it would be Aaron’s task to address the people, but the people would know that he was the “mouthpiece.” The word נביאך, means that just as a prophet is G’d’s mouthpiece, so Aaron will now become Moses’ mouthpiece. It is possible that this arrangement was out of the desire to show deference to the Egyptian establishment, in particular Pharaoh personally, who might be insulted if he received the word of G’d not even through his prophet but through the prophet’s mouthpiece. In spite of these considerations, in the end, Moses queried that the chances of Pharaoh paying heed to a stammerer such as he, was too much to expect.