Isa 6:5-7
Then I said, "Woe is me, I am doomed! For I am a man of unclean lips, living among a people of unclean lips; yet my eyes have seen the King, the LORD of hosts!" Then one of the seraphim flew to me, holding an ember which he had taken with tongs from the altar. He touched my mouth with it. "See," he said, "now that this has touched your lips, your wickedness is removed, your sin purged.".