Isaiah (Heb. Jeshaiah), son of Amoz, first of the greater Hebrew prophets, was a citizen of Jerusalem, who came forward as prophet about 740 B.C. (probable death-year of King Uzziah), and exercised his office till at least the close of the century. The main object of his prophesying was his people, Israel, sunk in social unrighteousness and idolatry; the subject was his people’s God, Jehovah, exalted or sovereign in righteousness, and, because there is nothing higher than righteousness, supreme over the whole world and its forces. From such a God to such people only punishment could pass, and the means for this was present in the great world-power of the day, the Assyrians, four of whose invasions of Palestine Isaiah predicted and lived to see. Be- cause, however, Jehovah’s honour and the existence of true religion upon earth were identified with the continuance of Israel’s national history, Isaiah promised the survival of a remnant, the stock of an imperial nation in the latter days, and centre for a whole world converted to Jehovah. This remnant required a leader and a rallying-place; and it was on these two points that Isaiah’s eloquence and hope reached their climax: that a great prince should arise in Judah—though sometimes he described the future without this personage—and that Zion, though closely besieged, should remain inviolate.
In the book of his name, the prophecies generally admitted to be Isaiah’s do not lie in chronological order. They may be re-arranged according to the four invasions of Palestine: Tiglath-pileser’s, 734–32; Shalmaneser’s and Sargon’s, 725–20; Sargon’s, 711–10; Sennacherib’s, 701. (1) In the prophecies held to be prior to the first invasion (ii.–x. 4: some add x. 5–34, and xvii. 1–14) Isaiah describes his call, arraigns both states of Israel, intimates their invasion, but with a different result for each. To north Israel he holds out no hope: in the worst that can happen to Judah, Zion shall stand, and David’s dynasty survive in a prince, whose birth Isaiah predicts as almost immediate, whom he hails as a deliverer from the Assyrians, but his ascriptions to whom are applied by the New Testament and Christian theology to Jesus Christ. Tiglath-pileser retired taking only a small part of north Israel captive. (2) In prophecies of the next invasion (xxviii. and most probably x. 5–xi.) Isaiah repeated the doom of north Israel, and his word was vindicated by the fall of Samaria in 721 and captivity of the people. He warned Judah again, but defied the Assyrian to take Zion, and expanded his prospect of the coming prince and the glory of the nation. Hezekiah, his friend, was now on the throne, and their joint work of abolishing the idols may have begun. (3) About the invasion of 711–10 there is difficulty. Did it comprise Judah? Sayce, Cheyne, &c. say it did, and assign to it Isaiah, x. 5–34, xxii., and xxxvi. 1, where they read Sargon for Sennacherib. But of an invasion of Judah by Sargon we have no direct evidence, and hence other critics (Driver, Robertson Smith, &c.) assign to this period only xx., xxi. 1–10, perhaps xvi. 13–14 (the rest of xv.–xvi. being earlier), and the events in xxxviii. and xxxix. (4) With 705—the revolt of Sargon’s vassals against Sennacherib, his successor, and Sennacherib’s preparations to reduce them—we reach the most fertile period of Isaiah’s prophesying. In xxix.–xxxii. he denounces Jewish intrigues with Egypt, predicts the siege and deliverance of Zion, and promises to faith and sincerity a glorious future. In another set of oracles to foreign nations, not all dating from this time, xiv. 24–32, perhaps xvii. 12–14, xviii., xix., xxi., xxiii., he intimates to a number of tribes the futility of their resistance to Assyria, and affirms that only Zion shall stand. In 701 Sennacherib overran Judah, and seems to have been bought off by Hezekiah, only, however, to send back a corps under the Rabshakeh to demand Zion’s surrender. It was this corps whose sudden withdrawal, upon news of a great disaster to the main army at Pelusium, set Jerusalem free, and so gloriously vindicated Isaiah’s word. His orations during these events are probably chap. i., describing the devastation of Judah; xxii., the panic and profligacy of the capital on the first appearance of the enemy; and xxxiii., the prophet’s final triumph at the Assyrian withdrawal; with the detailed narrative of events, xxxvi. 2–xxxvii. After this triumph in 701 it is very uncertain that we have anything more from Isaiah, except it be the latter half of xix., which has been called his 'swan-song.' Of his end we know nothing: a tradition exists that he was sown to death in the persecution of Manasseh (cf. Epistle to Hebrews, xi. 37; Gemara, Jebamoth, 49 b, and Sanh. 103 b; Joseph. Antiq. x. 31).
There still remains a large portion of the Book of Isaiah, xiii.-xiv. 23, xxiv.-xxvii., xxxiv., xxxv., and xl.-lxvi. The first doubts as to the authenticity of these were started by Aben-Ezra, and followed up by Koppe (1779), who suspected that xl.-lxvi. were of later date, and after him by an increasing, and now the main, body of critics on the Continent and in Britain—Gesenius, Hitzig, Kuobel, Umbreit, Ewald, A. B. Davidson, Cheyne, Driver, Robertson Smith, Kuenen, Wellhausen, &c.; and to a less degree, Delitzsch, Bredenkamp, Orelli, &c. No critic of any eminence now claims all sixty chapters for Isaiah; and indeed the belief that they were all his could only have originated through the taking for granted that the title of chap. i. covers the whole book—an opinion falsified by the appearance of titles for some of the following chapters and their absence from others. None of the chapters in question, save xiii., claim to be Isaiah's, and that they are not his may be argued, apart from the uncertain and confusing testimony of style, vocabulary, &c., upon grounds of historical evidence. The circumstance and horizon of these prophecies are entirely different from those of the authentic oracles. Assyria is no more the dominant world-power, nor Zion the inviolate fortress of God. The Jews are not in their own land: they are either in exile or just returned. It is no more the repulse of the invader or the recovery of Zion from siege that is predicted; but the overthrow of the tyrant in his own land, the redemption of a captive people, the laying down of a highway for the return of exiles, the rebuilding of the city, and the resumption of worship. Exile is not foretold, nor the effort made to lift the imagination to it as certain. It is described as present: the people are addressed as in exile, their conscience is appealed to as the conscience of a people who have suffered and acknowledge their penalty. In the case of xl.-lxvi. there is an additional argument. In some of these chapters Cyrus, who appeared about 550 or more than a century after Isaiah's death, is not only named as the deliverer of the exiles, and described as existing in the flesh; but in a debate (chap. xli. ff.) about Jehovah's righteousness—i.e. his fidelity to his ancient promises of deliverance and his ability to perform them—Cyrus is presented both to Jew and heathen as a living proof that these promises are about to be fulfilled—which surely would have been an utterly vain proceeding, if Cyrus were not already there, visible to all men. This very definite evidence overbears not only the resemblances in style between xl.-lxvi. and Isaiah's own oracles, but also such facts as that Isaiah foresaw the Babylonian captivity (xxxix.) or that he once wrote from the standpoint of a much larger exile than happened in his own day (xi.). It is quite possible, though incapable of proof, that the disputed prophecies contain fragments from Isaiah himself. That they contain at least pre-exilic fragments is more certain: lvi. 9-lvii. 11 implies that the Jewish state still exists, and bears traces of an origin in Palestine. By some lviii. ff., especially lxiii.-lxvi., are held to be post-exilic. Originally in the Jewish canon the Book of Isaiah seems to have followed Ezekiel, a fact which seems to confirm the late date of at least parts of the book.
See Commentaries by Alexander (1847; new ed. 1875), Ewald, Delitzsch (trans. 1891), Orelli (trans. 1891), and the present writer (in 'Expositor's Bible,' 1891); Driver's Isaiah: his Life and Times (1888); Kennedy's Unity of Isaiah (1891); works by Cheyne (1870-95); and Matthew Arnold's two books on Isaiah.