The historical situation in Isa. 40 ff. would of itself be conclusive against Isaiah's authorship; but it is not the only proof of the contrary. The author of these chapters has not inappropriately been called the theologian among the prophets. His idea of God is conspicuously more advanced than that of the prophets of the eighth century; it lies in the same line with the monotheism of Deuteronomy and Jeremiah, but lies beyond them. And it is characteristic that, in contrast to the older prophets, this one reasons about it. He argues the omnipotence of God in history from his omnipotence in creation, and makes large use of the evidence from the fulfilment of prophecy to prove that Jehovah is the only God; he can predict because he foreordains and brings to pass. With him begins the polemic, not against the worship of heathen gods, but against their existence. What the heathen bow down to are naught but helpless, senseless idols, the work of their own hands. He is fond of inviting his readers to an image-maker's shop to see how a god is made (see, e.g., Isa. xliv. 9-20). Such are the impotent gods that the Babylonians expect to save them out of the hands of the creator of the world! The style of Isa. 40 ff. is not less decisive. Translation necessarily in large measure effaces the differences, but even in translation a comparison of two passages on similar themes such as Isa. x. 5-19 and Isa. 47 may perhaps give some impression of them. The style of Isaiah and his contemporaries--Amos, Hosea, Micah--is concise and pregnant, the sentences are short and have often an oracular ring. The author of Isa. 40 ff. writes with a freer pen in flowing periods; he develops his thought and his figures more at large; if he is obscure, it is seldom from compression. Here again, Deuteronomy and Jeremiah, the whole literature of the seventh century, is an intermediate stage. The later author is a poet, as Isaiah is, but with other themes and in other forms; compare, e.g., Isa. 5 with Isa. xlii. 1-9. In short, each has a highly characteristic style, and the two are totally different.