Isaiah 6:5
5 And I said: “Woe is me! yFor I am lost; zfor I am a man of unclean lips, and I dwell in the midst of a people of unclean lips; for my eyes have seen the aKing, the Lord of hosts!”
Exodus 6:12
12 But Moses said to the Lord, “Behold, the people of Israel have tnot listened to me. How then shall Pharaoh listen to me, for uI am of uncircumcised lips?”