Isaiah 6:4-8

And the posts of the door were shaken by the voice of him who cried out, and the house was filled with smoke. So I said: “Woe is me, for I am undone! Because 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 King, The LORD of hosts.” Then one of the seraphim flew to me, having in his hand a live coal which he had taken with the tongs from the altar. And he touched my mouth with it, and said: “Behold, this has touched your lips; Your iniquity is taken away, And your sin purged.” Also I heard the voice of the Lord, saying: “Whom shall I send, And who will go for Us?” Then I said, “Here am I! Send me.”