Komentaryo sa Exodo 6:12: Rashi, Ramban, Sforno & Or HaChaim

ואיך ישמעני פרעה HOW THAN SHALL PHARAOH HEAR ME? — This is one of the ten inferences from minor to major which are found in the Bible (Genesis Rabbah 92:7).

BEHOLD, THE CHILDREN OF ISRAEL HAVE NOT HEARKENED UNTO ME because You have done nothing [for Israel] so that my words should be acceptable to them. AND HOW THEN SHALL PHARAOH HEAR ME? AND besides, I AM OF UNCIRCUMCISED LIPS, and I am not fit to speak before a great king.
It is possible to explain that Moses thought that due to his deficiency — for he was of uncircumcised lips — the children of Israel would not hearken to him, for he could not frame [words] to speak⁶¹Judges 12:6. kindly to them, words of good cheer and comfort, and all the more how could he speak to Pharaoh?
Now the reason that Moses again broached this argument [of his speech-impediment, when he had already mentioned it above in Chapter 4, Verse 10], is that G-d did not originally command him that he was to speak before Pharaoh. He merely said, And thou shalt come, thou and the elders of Israel, unto the king of Egypt, and ye shall say unto him.⁶²Above, 3:18. In that case it was possible that the elders should speak [before Pharaoh] and Moses would remain silent. Then Moses said that he was ashamed even to speak to the people, saying, I am not a man of words.⁶³Ibid., 4:10. Whereupon the Holy One, blessed be He, answered him, And he [Aaron] shall be thy spokesman unto the people.⁶⁴Ibid., Verse 16. And so indeed Moses and Aaron did when they first came to the people, as it is said, And Aaron spoke all the words which the Eternal had spoken unto Moses, and did the signs in the sight of the people.⁶⁵Ibid., Verse 30. But now Moses himself was commanded, Wherefore say unto the children of Israel: I am the Eternal,⁶⁶Verse 6. and he did speak to them as He commanded him, but they did not hearken to him.⁶⁷Verse 9. Now when He again commanded Moses to speak to Pharaoh,⁶⁸Verse 11. Moses said, “How can I speak to him, I who am of uncircumcised lips.” Then the Holy One, blessed be He, associated Aaron with him, and gave both of them a charge unto the children of Israel,⁶⁹Verse 13. that they should say to them whatever He will command them, and unto Pharaoh⁶⁹Verse 13. to bring them forth out of his land. Now Rashi commented: “[And He gave them a charge unto the children of Israel, and unto Pharaoh, king of Egypt]. That is to say, He gave them a command with regard to the children of Israel and His mission on which He had sent them to Pharaoh.” But there is no need for this.⁷⁰According to Rashi, the command of His mission to Pharaoh was the one with regard to Israel. But according to Ramban, there was also a command with regard to Israel, as explained in the text.

הן בני ישראל לא שמעו אלי, he believed that this was due to the fact that from the moment he had started speaking to Pharaoh the latter had become worse in his attitude and the people, putting two and two together, had concluded that his mission had failed. If he felt that way, Pharaoh would certainly not pay any heed to him and continue doing what he liked.

ערל שפתים OF UNCIRCUMCISED LIPS — It really means obstructed as regards the lips. So, too, in respect to all forms derived from ערל I say that they signify obstructed. E. g. (Jeremiah 6:10) “their ear is עֲרֵלָה — stopped up so that it will not hear; (Jeremiah 9:25) “עַרְלִי in heart” — their hearts are closed so that they will not understand; (Habakkuk 2:16) “Drink thou, also וְהֵעָרֵל” — and become thou closed up (in thy senses) through intoxication caused by the cup of curse mentioned in that passage; the foreskin (ערלה) of the flesh is so called because the membrum is closed up and covered by it; (Leviticus 19:23) וערלתם ערלתו signifies, make for it (the tree) a closure (אוטם) and cover by means of an inhibition that will prove a barrier against eating it; (Leviticus 19:23 “Three years shall it be to you as ערלים” — it shall be closed up and covered and barred so that it many not be eaten.