[4:10] 1 sn Now Moses took up another line of argumentation, the issue of his inability to speak fluently (vv. 10-17). The point here is that God’s servants must yield themselves as instruments to God, the Creator. It makes no difference what character traits they have or what weaknesses they think they have (Moses manages to speak very well) if God is present. If the sovereign God has chosen them, then they have everything that God intended them to have.
[4:10] 2 tn The word בִּי (bi) is a particle of entreaty; it seeks permission to speak and is always followed by “my lord” or “my Lord.” Often rendered “please,” it is “employed in petitions, complaints and excuses” (W. H. C. Propp, Exodus 1–18 [AB], 213).
[4:10] 3 tn The designation in Moses’ address is אֲדֹנָי (’adonay), a term of respect and deference such as “lord, master, sir” but pointed as it would be when it represents the tetragrammaton. B. Jacob says since this is the first time Moses spoke directly to Yahweh, he did so hesitatingly (Exodus, 87).
[4:10] 4 tn When a noun clause is negated with לֹא (lo’), rather than אֵין (’en), there is a special emphasis, since the force of the negative falls on a specific word (GKC 479 §152.d). The expression “eloquent man” is אִישׁ דְּבָרִים (’ish dÿvarim, “a man of words”). The genitive may indicate a man characterized by words or a man who is able to command or control words. Moses apparently is resigned to the fact that he can do the signs, but he knows the signs have to be explained.
[4:10] 5 tn Heb “also from yesterday also from three days ago” or “neither since yesterday nor since before that” is idiomatic for “previously” or “in the past.”
[4:10] 6 tn The two expressions are כְבַד־פֶּה (khÿvad peh, “heavy of mouth”), and then כְבַד לָשׁוֹן (khÿvad lashon, “heavy of tongue”). Both use genitives of specification, the mouth and the tongue being what are heavy – slow. “Mouth” and “tongue” are metonymies of cause. Moses is saying that he has a problem speaking well. Perhaps he had been too long at the other side of the desert, or perhaps he was being a little dishonest. At any rate, he has still not captured the meaning of God’s presence. See among other works, J. H. Tigay, “‘Heavy of Mouth’ and ‘Heavy of Tongue’: On Moses’ Speech Difficulty,” BASOR 231 (1978): 57-67.