Why did Moshe insert the word "Gam" three times?
Rashi: To teach us of three days that Hashem spent at the burning bush convincing Moshe to undertake the Shelichus. 1
Ramban: Moshe was simply saying that he had had a speech defect ever since his youth, and that the same defect was still present. 2
Why did Hashem not cure Moshe's speech defect?
Ramban #1: Because he did not ask Him to. 1
Ramban #2 (citing the Midrash): Hashem specifically wanted Moshe's speech defect to remain, to add to the miracle. 2
Ramban #3: It was the result of Hashem's anger 3 - a punishment for refusing to accept the Shelichus.
Rashbam: Moshe did not have a speech defect at all. 4 His argument was that he was not sufficiently conversant with the Egyptian language to appear before Pharaoh. 5
Ramban: Moshe, for his part, did not ask Hashem to cure him, because he did not want to go (Refer to 4:10:3:1). So he thought that, since it is not dignified to appear before Pharaoh in the Name of Hashem in that state, Hashem would surely pick someone else to go.
That a person who could not speak properly was able to converse with Pharaoh and issue him with instructions flawlessly.
See 4:14.
See Rashbam.
Rashbam: Since he fled the country in his youth, and now (upon his return) he was eighty.
Moshe was otherwise physically sound! On a conceptual level, why was he blemished in his mouth specifically?
What was Moshe's basic reason for refusing to accept the Shelichus?
Rashi: Because he did not want to accept a position that rendered him senior to his brother, Aharon. 1
Ramban (to 4:13): It was due to his extreme humility; 2 He simply could not conceive aggrandizing himself, to speak to the king and tell him that Hashem had sent him, and to take Yisrael out of Egypt and to be their king.
Moshav Zekenim (to 3:12): He feared that Pharaoh wanted to kill him. 3
Rashi: Who was (three years) older than he, and who was already a Navi (as the Pasuk in Shmuel I 2:27 indicates).
Ramban: See Bamidbar 12:3.
What is "Lo Ish Devarim"?
Hadar Zekenim: Sheluchim of the nations know all 70 languages. I do not know even mine! 1
QUESTIONS ON RASHI
Rashi writes: "'Kevad Peh' (lit. heavy of mouth') - I.e., I speak with difficulty." Why interpret this way?
Gur Aryeh: The phrase cannot be literal; a person does not feel heaviness in his mouth.
Rashi writes that "Gam" is written three times to teach three days. We hold that an inclusion after an inclusion comes to exclude!
Moshav Zekenim: An inclusion after an inclusion comes to exclude only when they include the same matter. Here, they include different days.