Isaiah's vision of the Lord
In the year King Uzziah died, Isaiah saw the Lord enthroned in the temple, surrounded by seraphim crying “Holy, holy, holy,” and answered God's call.
I heard the Lord’s voice, saying, “Whom shall I send, and who will go for us?” Then I said, “Here I am. Send me!”
Isaiah 6:8 (World English Bible)
Isaiah cried out that he was a man of unclean lips. A seraph touched his mouth with a burning coal from the altar and declared his guilt taken away. When God asked whom he should send, Isaiah volunteered. John says Isaiah saw Christ's glory (John 12:41).
Isaiah prophesied for over forty years, under Uzziah, Jotham, Ahaz, and Hezekiah, and his book contains many of the Old Testament's clearest prophecies of the Messiah.
Dating notes
“In the year that King Uzziah died” (Isaiah 6:1), 759 BC in Ussher.