Chapters 40–55 in the Book of Isaiah are believed to be the work of a prophet who lived with the Hebrew exiles during the Babylonian captivity. Because this prophet's real name is unknown and his work has been preserved in the collection of writings that include the prophecies of the earlier Isaiah, he is usually designated as Deutero-Isaiah — the second Isaiah. The chapters attributed to this prophet of the exile include some of the noblest religious ideals found in the entire Old Testament. The prophet was a pure monotheist. Rejecting the idea of Yahweh as a god who belonged only to the Hebrews, Deutero-Isaiah boldly proclaimed Yahweh as the only true God of the entire universe. He maintained that the so-called gods of foreign nations were but figments of the imagination. His conception of the people of Israel was also unique in that he regarded them as Yahweh's servants, whose primary function in the world is to carry religion to the ends of the earth. He made explicit an interpretation of history that, although it had been implied in the teachings of the earlier prophets, had never been stated as clearly by any of them. Finally, he introduced a new concept to account for the sufferings of people that could not, in all fairness, be explained as punishment for sins.
Deutero-Isaiah faced the task of giving new hope and encouragement to the exiles, who were on the verge of despair, feeling either that Yahweh had forsaken them entirely or that Yahweh's power had been broken by the superior gods of the Babylonians. To these disheartened people, Deutero-Isaiah calls out, "Here is your God!" He assures them that Yahweh has not forsaken the exiled people; neither has Yahweh been defeated by the Babylonians or any other foreign power. Yahweh is the supreme ruler of the universe, and all the nations of the earth are subject to him: "Surely the nations are like a drop in a bucket; they are regarded as dust on the scales." And again, "Before him all the nations are as nothing; they are regarded by him as worthless and less than nothing." Deutero-Isaiah ridicules people who bow down before man-made idols and who claim that these idols are representations of their gods. The only true God cannot be represented or symbolized by an image because there are no objects in nature to which he can be compared. Yahweh is the creator of the heavens and the earth. Whatever exists is dependent on him. He alone has the power to create and is the only presence whose purpose can be discerned in the course of history: "He sits enthroned above the circle of the earth, and its people are like grasshoppers. . . . He brings princes to nought and reduces the rulers of this world to nothing."
To those people who have grown weary of their captivity and who have despaired that the time will never come when they can return to their homeland, Deutero-Isaiah has a message of comfort and of hope: The time has arrived when warfare is over; their punishment is accomplished. Yahweh declares that already the captives have been punished too much, and he has called Cyrus, the Persian king, to take appropriate steps for their liberation. Yahweh is now ready to lead them himself. He will go before them, making the rough places smooth and gently carrying in his bosom the ones who are unable to travel by themselves. Yahweh's sovereignty over the nations of the earth is illustrated in Deutero-Isaiah's conception of history. Humans may think they have complete control over the course of events, but they are mistaken. Yahweh orders events that make up the historical process. Although his order is moral rather than mechanical and allows for choice on the part of human beings, nevertheless it establishes a relationship between cause and effect that remains constant.
Yahweh's constancy forms the basis for predictions. In this connection, Yahweh's power and foreknowledge cannot be matched by any of the foreign nations' gods. Speaking about this point, Deutero-Isaiah says for Yahweh, "Remember the former things, those of long ago; I am God, and there is no other; I am God, and there is none like me. I make known the end from the beginning, from ancient times, what is still to come. I say: My purpose will stand, and I will do all that I please."
In a series of poems called "Songs of the Suffering Servant," Deutero-Isaiah sets forth his greatest contribution to Israel's religious ideals. He points out the purpose and the opportunity that lie behind the unmerited suffering on the part of comparatively innocent persons. The problem that troubled Habakkuk — why the just suffer and the wicked prosper — had become one of the major issues for the exiles in Babylon. Granted, the exiles made many mistakes, but they were not as unjust or as wicked as the nations to which they were made captives. If suffering is to be interpreted as punishment for sins, it ought to be distributed on a different basis than what the exiles experienced and observed. Deutero-Isaiah does not deny that at times suffering may be a just punishment for sins, but he insists that not all suffering should be interpreted in this way. Having in mind the captivity of the Israelite people, he is able to see in their captivity something more than punishment for the mistakes they made. He views the captivity as an opportunity to do something generous and noble for the benefit of those who held them in bondage. Instead of the Israelites suffering for their own sins, he sees in the experience the possibility of a voluntary suffering because of the sins of others. Such suffering could be the means of winning over the Israelites' enemies to a new way of living that would be in harmony with the principles of justice and righteousness.
Deutero-Isaiah's thoughts on voluntary suffering were indeed new ways in which the captives might find at least a partial explanation — the realization of a divine purpose — for the hardships that they experienced. The prophet sees the Israelite people as Yahweh's servants and as his chosen people, but chosen for the task of suffering in order that true religion might be brought to those who could not be reached in any other way. What could not be accomplished by force or argument might be achieved through the power of love as manifested in the voluntary suffering of the innocent for the sake of the guilty. Speaking for Yahweh, Deutero- Isaiah says to the people of Israel and Judah, "It is too small a thing for you to be my servant to restore the tribes of Jacob and bring back those of Israel I have kept. I will also make you a light for the Gentiles, that you may bring my salvation to the ends of the earth."
No prophet of the Old Testament ever reached loftier heights in his understanding of religion than did Deutero-Isaiah. In his conception of Yahweh as the creator of the heavens and the earth, he made a sharp distinction between Yahweh and the deities of foreign nations. Yahweh was the presence on which all existence depended; he could not be adequately conceived as like any of the objects in the created universe. Although Deutero-Isaiah speaks of Yahweh as a person — if the deity is to have any meaning for human beings, it must be conceived in terms that have been drawn from experience, and personality is the most appropriate symbol that can be found — Yahweh does not have a human personality in every respect, but only in some of them.
Deutero-Isaiah's interpretation of history recognizes that the course of events is something more than a chaotic sequence without meaning or order. A divine element, as well as a human element, exists in history; a purpose is achieved through the historical process, which is what Deutero-Isaiah means when he declares that Yahweh knows the end from the beginning. Deutero-Isaiah's predictions do not imply that all of the things that happen are known in advance, nor do they imply that human beings cannot alter the course of events by the choices they make. Deutero-Isaiah's greatest achievement is his development of the idea of vicarious suffering. Although he was speaking primarily about the suffering of his own people, we must not think that he was attempting to give a historical account of the way only they were responding to their misfortunes. Rather, he was setting forth an ideal that, if followed, would throw new light on the question of unmerited suffering. People would realize that the situation in which they were placed provided an opportunity for them to exhibit to foreign nations the true spirit of their religion. Like the other prophets before him, Deutero-Isaiah never doubted that the divine purpose ultimately would be achieved, but the method by which it would be accomplished was something quite different from what was previously conceived. Vicarious suffering was an idea of great significance, and although it seems to have been too lofty an ideal for the majority of the people either to grasp or to follow, some individuals believed its truth. Through the centuries that followed, many occasions exemplified this ideal. Christians have long recognized that the life and death of Jesus of Nazareth are supreme examples of what Deutero-Isaiah proclaimed to his contemporary exiles in Babylon.