These facts are more broadly based than just at first sight appears. You cannot turn their flank by the argument that Hebrew prophets were in the habit of employing in their predictions what is called "the prophetic perfect"--that is, that in the ardour of their conviction that certain things would take place they talked of these, as the flexibility of the Hebrew tenses allowed them to do, in the past or perfect as if the things had actually taken place. No such argument is possible in the case of the introduction of Cyrus. For it is not only that the prophecy, with what might be the mere ardour of vision, represents the Persian as already above the horizon and upon the flowing tide of victory; but that, in the course of a sober argument for the unique divinity of the God of Israel, which takes place throughout chs. xli.-xlviii., Cyrus, alive and irresistible, already accredited by success, and with Babylonia at his feet, is pointed out as the unmistakable proof that _former_ prophecies of a deliverance for Israel are at last coming to pass. Cyrus, in short, is not presented as a prediction, but as the proof that a prediction is being fulfilled. Unless he had already appeared in flesh and blood, and was on the point of striking at Babylon, with all the prestige of unbroken victory, a great part of Isa. xli.-xlviii. would be utterly unintelligible.
This argument is so conclusive for the date of Second Isaiah, that it may be well to state it a little more in detail, even at the risk of anticipating some of the exposition of the text.
Among the Jews at the close of the Exile there appear to have been two classes. One class was hopeless of deliverance, and to their hearts is addressed such a prophecy as ch. xl.: _Comfort ye, comfort ye My people_. But there was another class, of opposite temperament, who had only too strong opinions on the subject of deliverance. In bondage to the letter of Scripture and to the great precedents of their history, these Jews appear to have insisted that the Deliverer to come must be a Jew, and a descendant of David. And the bent of much of the prophet's urgency in ch. xlv. is to persuade those pedants, that the Gentile Cyrus, who had appeared to be not only the biggest man of his age, but the very likely means of Israel's redemption, was of Jehovah's own creation and calling. Does not such an argument necessarily imply that Cyrus was already present, an object of doubt and debate to earnest minds in Israel? Or are we to suppose that all this doubt and debate were foreseen, rehearsed and answered one hundred and fifty years before the time by so famous a prophet as Isaiah, and that, in spite of his prediction and answer, the doubt and debate nevertheless took place in the minds of the very Israelites, who were most earnest students of ancient prophecy? The thing has only to be stated to be felt to be impossible.