Let us understand, therefore, at this very outset, that in discussing the question of the authorship of "Second Isaiah," we are not discussing a question, upon which the text itself makes any statement, or into which the credibility of the text enters. No claim is made by the Book of Isaiah itself for the Isaian authorship of chs. xl.-lxvi.
A second fact in Scripture, which seems at first sight to make strongly for the unity of the Book of Isaiah, is that in the New Testament, portions of the disputed chapters are quoted by Isaiah's name, just as are portions of his admitted prophecies. These citations are nine in number.[3] None is by our Lord Himself. They occur in the Gospels, Acts and Paul. Now if any of these quotations were given in answer to the question, Did Isaiah write chs. xl.-lxvi. of the book called by his name? or if the use of his name along with them were involved in the arguments which they are borrowed to illustrate (as, for instance, is the case with David's name in the quotation made by our Lord from Psalm cx.), then those who deny the unity of the Book of Isaiah would be face to face with a very serious problem indeed. But in none of the nine cases is the authorship of the Book of Isaiah in question. In none of the nine cases is there anything in the argument, for the purpose of which the quotation has been made, that depends on the quoted words being by Isaiah. For the purposes, for which the Evangelists and Paul borrow the texts, these might as well be unnamed, or attributed to any other canonical writer. Nothing in them requires us to suppose that Isaiah's name is mentioned with them for any other end than that of reference, viz., to point out that they lie in the part of prophecy usually known by his name. But, if there is nothing in these citations to prove that Isaiah's name is being used for any other purpose than that of reference, then it is plain--and this is all that we ask assent to at the present time--that they do not offer the authority of Scripture as a bar to our examining the evidence of the chapters in question.
It is hardly necessary to add that neither is there any other question of doctrine in our way. There is none about the nature of prophecy, for, to take an example, ch. liii., as a prophecy of Jesus Christ, is surely as great a marvel if you date it from the Exile as if you date it from the age of Isaiah. And, in particular, let us understand that no question need be started about the ability of God's Spirit to inspire a prophet to mention Cyrus by name one hundred and fifty years before Cyrus appeared. The question is not, _Could_ a prophet have been so inspired?--to which question, were it put, our answer might only be, God is great!--but the question is, _Was_ our prophet so inspired? does he himself offer evidence of the fact? Or, on the contrary, in naming Cyrus does he give himself out as a contemporary of Cyrus, who already saw the great Persian above the horizon? To this question only the writings under discussion can give us an answer. Let us see what they have to say.
Apart from the question of the date, no chapters in the Bible are interpreted with such complete unanimity as Isa. xl.-xlviii. They plainly set forth certain things as having already taken place--the Exile and Captivity, the ruin of Jerusalem, and the devastation of the Holy Land. Israel is addressed as having exhausted the time of her penalty, and is proclaimed to be ready for deliverance. Some of the people are comforted as being in despair because redemption does not draw near; others are exhorted to leave the city of their bondage, as if they were growing too familiar with its idolatrous life. Cyrus is named as their deliverer, and is pointed out as already called upon his career, and as blessed with success by Jehovah. It is also promised that he will immediately add Babylon to his conquests, and so set God's people free.