This short review--in which, for the sake of getting a complete view of our subject, we have anticipated a little--has shown that Israel had enough within themselves, in the teaching of their prophets and in the lessons of their own history, to account for that consummate expression of Jehovah's Godhead, which is contained in our prophet, and to which every one allows the character of an absolute monotheism. We shall find this, it is true, to be higher and more comprehensive than anything which is said about God in pre-exilic Scriptures. The prophet argues the claims of Jehovah, not only with the ardour that is born of faith, but often with the scorn which indicates the intellect at work. It is monotheism, treated not only as a practical belief or a religious duty, but as a necessary truth of reason; not only as the secret of faith and the special experience of Israel, but also as an essential conviction of human nature, so that not to believe in One God is a thing irrational and absurd for Gentiles as well as Jews. God's infinitude in the works of creation, His universal providence in history, are preached with greater power than ever before; and the gods of the nations are treated as things, in whose existence no reasonable person can possibly believe. In short, our great prophet of the Exile has already learned to obey the law of Deuteronomy as it was expounded by Christ. Deuteronomy says, _Thou shalt love Jehovah thy God with all thine heart, with all thy soul, and with all thy strength_. Christ added, _and with all thy mind_. This was what our prophet did. He held his monotheism _with all his mind_. We shall find him conscious of it, not only as a religious affection, but as a necessary intellectual conviction; which if a man has not, he is less than a man. Hence the scorn, which he pours upon the idols and mythologies of his conquerors. Beside his tyrants, though in physical strength he was but a worm to them, the Jew felt that he walked, by virtue of his faith in One God, their intellectual master.
We shall see all this illustrated later on. Meantime, what we are concerned to show is, that there is enough to account for this high faith within Israel themselves--in their prophecy and in the lessons of their history. And where indeed are we to be expected to go in search of the sources of Israel's monotheism, if not to themselves? To the Babylonians? The Babylonians had nothing spiritual to teach to Israel; our prophet regards them with scorn. To the Persians, who broke across Israel's horizon with Cyrus? Our prophet's high statement of monotheism is of earlier date than the advent of Cyrus to Babylon. Nor did Cyrus, when he came, give any help to the faith, for in his public edicts he owned the gods of Babylon and the God of Israel with equal care and equal policy. It was not because Cyrus and his Persians were monotheists, that our prophet saw the sovereignty of Jehovah vindicated, but it was because Jehovah was sovereign that the prophet knew the Persians would serve His holy purposes.