Exodus 6:12

But Moses said to God, “Who am I, that I should go to Pharaoh, and that I should bring the sons of Israel out of Egypt?”

Then Moses said to Yahweh, “Please, Lord, I have never been a man of words, neither recently nor in time past, nor since You have spoken to Your slave; for I am one with a hard mouth and a hard tongue.”

But Moses said before Yahweh, “Behold, I am of uncircumcised lips; how then will Pharaoh listen to me?”

Then I said, “Woe is me, for I am ruined! For I am a man of unclean lips, And I live among a people of unclean lips; For my eyes have seen the King, Yahweh of hosts.”