The book of Isaiah is one of the longest in the Old Testament. It records the messages delivered by its eponymous prophet, who served in Judah during the eighth century BCE, at the height of the Assyrian crisis. Although the text of Isaiah bears no structural indications of internal divisions, there is a major transition in tone that marks the first part of the book (Chapters 1-39) from the second (Chapters 40-66). The first section carries overtones of warning and judgment, delivering oracles against Israel and other nations, while the second section is replete with assurances of God’s love and beautiful, hope-filled prophecies of the future. Some scholars suggest that the second section reflects a later period of composition, perhaps from an exilic or post-exilic context.

Isaiah is largely poetic, containing only a few narrative sections, many of which narrate details of Isaiah’s life or of Judah’s national situation during the Assyrian crisis. The book contains prophecies not only aimed toward its own time and place, but also a few which appear to foreshadow a coming messianic figure. Many such prophecies are interpreted in later Christian tradition as applying to Jesus.