This book, as is true of all the prophetical books, derives its name from the prophet whose messages it records. The unity of Isaiah, a problem related to authorship and contents, has been the subject of much debate. The message of the book is twofold: judgment upon Judah for her sins (1-39), and comfort and hope for an exiled people (40-66). In these messages of encouragement are found some of the most graphic portrayals of the Messiah in the Old Testament.