Prophets, kings, and the mysterious Servant.
Isaiah's cast is not a cast in the narrative sense — most of the book is oracular poetry, not story. The figures below are those the book centres on or addresses: the 8th-century prophet himself, the kings he counsels and confronts, the mysterious Servant of Second Isaiah, and the God who is named above all others as the Holy One of Israel.
The 8th-century BCE prophet of First Isaiah. Active from about 740 to 700, during the reigns of four kings of Judah. He sees the Lord in the temple in chapter 6, preaches judgement against social injustice and against Egypt as a political ally, and advises Hezekiah during the Assyrian crisis. His disciples preserved and extended his oracles into the tradition that became the whole book.
The king who receives both the prophet's deepest trust and the book's most extended royal narrative. He confronts the Assyrian invasion of 701, prays in the temple, receives Isaiah's oracle of deliverance, falls ill and recovers, and is warned — after showing his treasury to the Babylonian envoys — that the coming exile will be to Babylon. The type of the king who trusts God rather than foreign alliance.
King of Assyria, the historical antagonist of First Isaiah's narrative section. His invasion of 701 is the crisis that the prophet's word of trust answers. His annals confirm the siege of Jerusalem; the city was not taken. He returns to Nineveh and is assassinated by his sons (37:38), fulfilling Isaiah's oracle precisely.
The king to whom Isaiah delivers the Immanuel sign in chapter 7, during the Syro-Ephraimite crisis of 735–732 BCE. Where Hezekiah trusts Isaiah's word, Ahaz is the foil: afraid, unwilling to ask a sign, seeking Egyptian and Assyrian alliance instead of the prophet's counsel. The contrast between Ahaz and Hezekiah structures much of First Isaiah's understanding of kingship.
The figure of the four Servant Songs (42, 49, 50, 52–53). Not a character in a narrative but a figure invoked in oracular poetry, whose identity is left precisely ambiguous: Israel in 49:3, yet given a mission to Israel in 49:5–6. He bears the iniquity of many through suffering. His interpretive history — read as Israel by Jewish tradition, as the Messiah and then as Christ by Christian tradition — is one of the most consequential in all of religious literature.
Named in 45:1 as the Lord's anointed — the only non-Israelite given this title in the Hebrew Bible. The Persian king who conquered Babylon in 538 BCE and issued the decree permitting Jewish exiles to return. Second Isaiah presents him as the instrument of God's redemptive purpose, chosen by name before he was born. The theological audacity of this claim — that God names and uses a pagan conqueror as his anointed — is central to Second Isaiah's universalist theology.
The most distinctive divine title in the book, occurring about twenty-five times. In First Isaiah: judge. In Second Isaiah: redeemer, shepherd, comforter. In Third Isaiah: glorifier of the new Jerusalem. The same God in all three registers — and the title itself is what holds the three Isaiahs together. He fills the temple with his train in chapter 6 and tends his flock like a shepherd in chapter 40, and both are the same Holy One.