Isaiah 6:5-7

5“Woe to me!” I cried. “I am ruined! For I am a man of unclean lips, and I live among a people of unclean lips, and my eyes have seen the King, the LORD Almighty.” 6Then one of the seraphim flew to me with a live coal in his hand, which he had taken with tongs from the altar.

7With it he touched my mouth and said, “See, this has touched your lips; your guilt is taken away and your sin atoned for.”