The prediction of the sudden raising of this siege was the equally natural corollary to another religious conviction, which held the prophet with as much intensity, as that which possessed him with the need of Judah's punishment. Isaiah never slacked his hold on the truth that in the end God would save Zion, and keep her for Himself. Through whatever destruction, a root and remnant of the Jewish people must survive. Zion is impregnable because God is in her, and because her inviolateness is necessary for the continuance of true religion in the world. Therefore as confident as his prediction of the siege of Jerusalem is Isaiah's prediction of her delivery. And while the prophet wraps the fact in vague circumstance, while he masks, as it were, his ignorance of how in detail it will actually take place by calling up a great natural convulsion, yet he makes it abundantly clear--as, with his religious convictions and his knowledge of the Assyrian power, he cannot help doing--that the deliverance will be unexpected and unexplainable by the natural circumstances of the Jews themselves, that it will be evident as the immediate deed of God. It is well for us to understand this. We shall get rid of the mechanical idea of prophecy, according to which prophets made exact predictions of fact by some particular and purely official endowment. We shall feel that prediction of this kind was due to the most unmistakeable inspiration, the influence upon the prophet's knowledge of affairs of two powerful religious convictions, for which he himself was strongly sure that he had the warrant of the Spirit of God. Into the easy, selfish politics of Jerusalem, then, Isaiah sent this thunderbolt, this definite prediction: that in a year or more Jerusalem would be besieged and reduced to the direst straits. He tells us that it simply dazed the people. They were like men suddenly startled from sleep, who are too stupid to read a message pushed into their hands (vv. 9-12).