Isaiah 6:6

2Above it stood the seraphims: each one had six wings; with twain he covered his face, and with twain he covered his feet, and with twain he did fly.

3And one cried unto another, and said, Holy, holy, holy, is the Lord of hosts: the whole earth is full of his glory.

4And the posts of the door moved at the voice of him that cried, and the house was filled with smoke.

5Then said I, 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 mine eyes have seen the King, the Lord of hosts.

6Then flew one of the seraphims unto me, having a live coal in his hand, which he had taken with the tongs from off the altar:

7And he laid it upon my mouth, and said, Lo, this hath touched thy lips; and thine iniquity is taken away, and thy sin purged.

8Also I heard the voice of the Lord, saying, Whom shall I send, and who will go for us? Then said I, Here am I; send me.

9And he said, Go, and tell this people, Hear ye indeed, but understand not; and see ye indeed, but perceive not.

10Make the heart of this people fat, and make their ears heavy, and shut their eyes; lest they see with their eyes, and hear with their ears, and understand with their heart, and convert, and be healed.