Isaiah

Isaiah is the longest of the prophets and the most often quoted in the New Testament. Saint Jerome called him “not so much a prophet as an evangelist” — so vivid are his foretellings of Christ's birth, ministry, passion, and triumph that the early Church read him almost as a fifth Gospel. The book bears the name of Isaiah son of Amos, who prophesied in Jerusalem during the reigns of Uzziah, Jotham, Ahaz, and Hezekiah (roughly 740–700 BC), through the Assyrian crises that nearly destroyed Judah.

The authorship of Isaiah is a question Catholic exegesis has long taken seriously. Tradition ascribes the entire book to the eighth-century prophet. Modern Catholic scholarship, since the Pontifical Biblical Commission's 1908 reply on Isaiah and the wider freedoms granted by Pius XII's Divino Afflante Spiritu (1943), generally distinguishes Isaiah of Jerusalem (chs. 1–39, the historical prophet) from later inspired authors writing in the Isaian tradition during the Babylonian exile (chs. 40–55) and the post-exilic restoration (chs. 56–66). The unity of voice and theology across the whole book is preserved by the prophetic school that gathered around the master.

The themes of Isaiah are vast: the holiness of the Lord (“Holy, holy, holy, the Lord God of hosts”, 6:3), the judgment that falls on Jerusalem and the nations, and the dazzling promise of restoration. At the heart of the book stand the four Servant Songs (42:1–9, 49:1–13, 50:4–11, 52:13–53:12) — the prophecies of a mysterious figure who will suffer for the sins of many. “He was wounded for our iniquities, he was bruised for our sins; the chastisement of our peace was upon him, and by his bruises we are healed” (53:5) is the most explicit Old Testament prophecy of the Passion.

Literarily, Isaiah falls into three movements. Chapters 1–39 deliver the eighth-century prophet's oracles of judgment against Judah, oracles against the nations, and the great Immanuel prophecies (“A virgin shall conceive and bear a son, and his name shall be called Emmanuel”, 7:14). Chapters 40–55, the “Book of Consolation,” speak to the exiles in Babylon: “Be comforted, be comforted, my people” (40:1). Chapters 56–66 address the returned community in Jerusalem with promises of new heavens and a new earth.

Isaiah saturates Catholic liturgy. The Advent and Christmas readings draw heavily from him — the Immanuel prophecy, the Prince of Peace (9:6), the wolf dwelling with the lamb (11:6). The Suffering Servant of chapter 53 is read on Good Friday. The vision of the heavenly liturgy in chapter 6 is the source of the Sanctus we sing at every Mass. The Catechism treats Isaiah as the prophetic foundation for the Church's teaching on Christ as Messiah, Servant, and Prince of Peace. To read Isaiah is to learn how Israel's hope took the precise shape that, centuries later, Christ would step forward to fulfill.