Isaiah 6:1–8 (ESV) —

1 In the year that King Uzziah died I saw the Lord sitting upon a throne, high and lifted up; and the train of his robe filled the temple.
2 Above him stood the seraphim. Each had six wings: with two he covered his face, and with two he covered his feet, and with two he flew.
3 And one called to another and said: “Holy, holy, holy is the LORD of hosts; the whole earth is full of his glory!”
4 And the foundations of the thresholds shook at the voice of him who called, and the house was filled with smoke.
5 And I said: “Woe is me! For I am lost; for 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!”
6 Then one of the seraphim flew to me, having in his hand a burning coal that he had taken with tongs from the altar.
7 And he touched my mouth and said: “Behold, this has touched your lips; your guilt is taken away, and your sin atoned for.”
8 And I heard the voice of the Lord saying, “Whom shall I send, and who will go for us?” Then I said, “Here I am! Send me.”