Representations to a ruler, Moses argued, required powers of speech. “I,” he said, “am not a man of words… I am slow of speech and slow of tongue” (Ex. 4:10).
Rashbam thought Moses was saying that his problem was with the Egyptian language. He had learned it as a child, but now he was 80 and his Egyptian was halting.
Ibn Ezra rejects this explanation as illogical, since what Moses actually said was that he was “slow of speech and slow of tongue”, which cannot be understood in any other way than that Moses had a speech defect. (It should be added that on various occasions Moses says of himself that he is a person of “uncircumcised lips”: e.g. Ex. 6:12, 30).
Ibn Ezra’s view is vindicated by the way the text proceeds: “Then God said to him, ‘Who made man’s mouth? Who makes a man dumb or deaf, clear-sighted or blind? Is it not I, the Lord? Now go, and I will be with your mouth and will teach you what to say!'” (Ex. 4:11-12).
On these verses Rashi utilises the Midrash Tanchuma to suggest that God gave Moses eloquence so that he could acquit himself properly before Pharaoh.
He also made Pharoah temporarily dumb so that he could not insist that Moses be put to death, the courtiers deaf so they could not hear any orders to do away with Moses, and the executioners blind so that Moses could elude them.
The statement that Moses overcame his speech defect is borne out by the rest of Pentateuchal history. Time after time we see him giving speeches without any apparent stammer, making rulings, and even questioning the Divine will.
It seems that necessity enables a person to rise above adversity, even in relation to clear speech.
Samson Raphael Hirsch asks why “a man who ordinarily stammers speaks clearly and flowingly in God’s mission”. He bases his explanation on the Hebrew words for the four categories that God refers to, illem (dumb), cheresh (deaf), pikke’ach (clear-sighted) and ivver (blind).
He derives illem from a root meaning to bind or tie up, implying that with God’s help the stammerer can untie his tongue.
He links cheresh with a verb that means to plough, for “the deaf have to ‘plough’ their own fields of thought, for no seeds are planted in the soil of their brains from outside” (note that the cheresh who has no hearing at all is unknown today).
Hirsch sees pikke’ach as a stronger form of a word that means to split or open out, implying someone who is wide-awake.
Ivver he links with or, the skin, and thus “a man of touch, a blind man whose perception of the external world depends solely on his sense of Touch”.
Everything thus depends on Divine assistance and personal effort.