John Gill Commentary Exodus 6:30

"And Moses said before Jehovah, Behold, I am of uncircumcised lips, and how shall Pharaoh hearken unto me?" — Exodus 6:30 (ASV)

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.