Isaiah is the supreme visionary of the Hebrew prophetic tradition. The book that bears his name contains both the most exalted vision of God's glory (the Seraphim crying "Holy, Holy, Holy") and the most anguished portrait of the Messiah's suffering (the Servant Songs). Isaiah holds together what most traditions separate: the transcendent glory and the sacrificial descent.
The Vision of the Throne (Isaiah 6)
"In the year that King Uzziah died, I saw the Lord, high and exalted, seated on a throne; and the train of his robe filled the temple. Above him were Seraphim, each with six wings: with two wings they covered their faces, with two they covered their feet, and with two they were flying. And they were calling to one another: 'Holy, holy, holy is the Lord Almighty; the whole earth is full of his glory.'"
The Seraphim ("burning ones") — angelic beings of pure fire, who cannot look upon God even as they attend Him. The threefold Kadosh (Trisagion) — the primal liturgy of heaven. Isaiah's response: "Woe to me! I am ruined! For I am a man of unclean lips." A Seraph takes a live coal from the altar and touches it to his lips: "Your guilt is taken away and your sin atoned for."
The Suffering Servant (Isaiah 52:13 - 53:12)
"He was despised and rejected by mankind, a man of suffering, and familiar with pain... Surely he took up our pain and bore our suffering... He was pierced for our transgressions, he was crushed for our iniquities; the punishment that brought us peace was on him, and by his wounds we are healed."
The Fourth Servant Song — the most detailed prophetic portrait of the Christic sacrifice in the Hebrew Bible. The one who bears the sins of the many. The one who is "cut off from the land of the living" yet whose sacrifice brings healing to the nations.
Emmanuel: "God With Us" (Isaiah 7:14)
"The virgin will conceive and give birth to a son, and will call him Immanuel."
The promise that God will not remain distant, transcendent, enthroned above the Seraphim — but will enter creation, take on flesh, and dwell among us. The Incarnation foretold.
The Peaceable Kingdom (Isaiah 11)
"The wolf will live with the lamb, the leopard will lie down with the goat... They will neither harm nor destroy on all my holy mountain, for the earth will be filled with the knowledge of the Lord as the waters cover the sea."