And Moses spake before the LORD, saying, Behold, the children of Israel have not hearkened unto me; how then shall Pharaoh hear me, who am of {d} uncircumcised lips?

(d) Or barbarous and rude in speech and by this word

(uncircumcised) is signified the whole corruption of man's nature.

Wesley's Notes

6:12 Behold, the children of Israel have not hearkened to me; they gave no heed to what I have said, how then shall Pharaoh hear me? - If the anguish of their spirit makes them deaf to that which would compose and comfort them, much more will his pride and insolence, make him deaf to that which will but exasperate him. Who am of uncircumcised lips - He was conscious to himself that he had not the gift of utterance.

Jamieson-Fausset-Brown Bible Commentary

12. how then shall . who am of uncircumcised lips?-A metaphorical expression among the Hebrews, who, taught to look on the circumcision of any part as denoting perfection, signified its deficiency or unsuitableness by uncircumcision. The words here express how painfully Moses felt his want of utterance or persuasive oratory. He seems to have fallen into the same deep despondency as his brethren, and to be shrinking with nervous timidity from a difficult, if not desperate, cause. If he had succeeded so ill with the people, whose dearest interests were all involved, what better hope could he entertain of his making more impression on the heart of a king elated with pride and strong in the possession of absolute power? How strikingly was the indulgent forbearance of God displayed towards His people amid all their backwardness to hail His announcement of approaching deliverance! No perverse complaints or careless indifference on their part retarded the development of His gracious purposes. On the contrary, here, as generally, the course of His providence is slow in the infliction of judgments, while it moves more quickly, as it were, when misery is to be relieved or benefits conferred.

Matthew Henry's Concise Commentary

6:10-13 The faith of Moses was so feeble that he could scarcely be kept to his work. Ready obedience is always according to the strength of our faith. Though our weaknesses ought to humble us, yet they ought not to discourage us from doing our best in any service we have to do for God. When Moses repeats his baffled arguments, he is argued with no longer, but God gives him and Aaron a charge, both to the children of Israel, and to Pharaoh. God's authority is sufficient to answer all objections, and binds all to obey, without murmuring or disputing, Php 2:14.