Isaiah's Encounter With The LORD

"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. 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. And one called to another and said:

'Holy, holy, holy is the Lord of hosts; the whole earth is full of his glory!'

And the foundations of the thresholds shook at the voice of him who called, and the house was filled with smoke. 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!'

Then one of the seraphim flew to me, having in his hand a burning coal that he had taken with tongs from the altar. And he touched my mouth and said: 'Behold, this has touched your lips; your guilt is taken away, and your sin atoned for.'"  (Isaiah 6:1-7)

     "The seraph pressed the white-hot coal to the lips of the prophet and seared them. The lips are one of the most sensitive parts of human flesh, the meeting point of the kiss. Here Isaiah felt the holy flame burning his mouth. The acrid smell of burning flesh filled his nostrils, but that sensation was dulled by the excruciating pain of the heat. This was a severe mercy, a painful act of cleansing. Isaiah's wound was being cauterized, the dirt in his mouth was being burned away. He was refined by holy fire.
     "In this divine act of cleansing, Isaiah experienced a forgiveness that went beyond the purification of his lips. He was cleansed throughout, forgiven to the core, but not without the awful pain of repentance. He went beyond cheap grace and the easy utterance "I'm sorry." He was in mourning for his sin, overcome with moral grief, and God sent an angel to heal him. His sin was taken away. His dignity remained intact. His guilt was removed, but his humanity was not insulted. The conviction that he felt was constructive. His was no cruel and unusual punishment. A second of burning flesh on the lips brought a healing that would extend to eternity. In a moment, the disintegrating prophet was whole again. His mouth was purged. He was clean."

R.C. Sproul, The Holiness of God, (Tyndale, 1998), p. 31.