In the year that King Uzziah died, I saw the LORD sitting on a throne, high and lofty; and the hem of his robe filled the temple. Seraphs were in attendance above him; each had six wings: with two they covered their faces, and with two they covered their feet, and with two they flew. And one called to another and said:

"Holy, holy, holy is the LORD of hosts;
the whole earth is full of his glory."

The pivots on the thresholds shook at the voices of those who called, and the house filled with smoke. And I said: "Woe is me! I am lost, for I am a man of unclean lips, and I live among a people of unclean lips; yet my eyes have seen the King, the LORD of hosts!"

Then one of the seraphs flew to me, holding a live coal that had been taken from the altar with a pair of tongs. The seraph touched my mouth with it and said: "Now that this has touched your lips, your guilt has departed and your sin is blotted out." Then I heard the voice of the LORD saying, "Whom shall I send, and who will go for us?" And I said, "Here am I; send me!"

--Isaiah 6:1-8