See Exodus 6:12.

And Moses said before the Lord, behold, I am of uncircumcised lips,.... As he had done, Exodus 6:13, and this is only a repetition of what is there said, in order to lead on to what is related in the following chapter:

how shall Pharaoh hearken unto me? so mean a person, and so poor a speaker, and he a mighty king, surrounded with wise counsellors and eloquent orators.

And Moses said before the LORD, Behold, I am of {l} uncircumcised lips, and how shall Pharaoh hearken unto me?

(l) The disobedience both of Moses and of the people, shows that their deliverance came only from God's free mercy.

6:14-30 Moses and Aaron were Israelites; raised up unto them of their brethren, as Christ also should be, who was to be the Prophet and Priest, the Redeemer and Lawgiver of the people of Israel. Moses returns to his narrative, and repeats the charge God had given him to deliver his message to Pharaoh, and his objection against it. Those who have spoken unadvisedly with their lips ought to reflect upon it with regret, as Moses seems to do here.Uncircumcised, is used in Scripture to note the unsuitableness there may be in any thing to answer its proper purpose; as the carnal heart and depraved nature of fallen man are wholly unsuited to the services of God, and to the purposes of his glory. It is profitable to place no confidence in ourselves, all our sufficiency must be in the Lord. We never can trust ourselves too little, or our God too much. I can do nothing by myself, said the apostle, but I can do all things through Christ which strengtheneth me.