Isaiah 6:5-10

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.” And He said, “Go, and tell this people: ‘Keep on hearing, but do not understand; Keep on seeing, but do not perceive.’ “Make the heart of this people dull, And their ears heavy, And shut their eyes; Lest they see with their eyes, And hear with their ears, And understand with their heart, And return and be healed.”