"By general consent, the Book of Isaiah is regarded as the supreme example of the prophetic literature of the Hebrew Bible. In loftiness of thought, beauty of diction, and rhetorical force the Book occupies a place of its own, [wrote A. Cohen, an Orthodox Jewish commentator in 1949]."
Especially coming from a pious Jew, what this assessment reveals is that one of the major factors at work in establishing the immense prestige of the Book of Isaiah was--and is--its literary stature. Whether emanating from a single person or several, the first thirty-nine chapters of the Book of Isaiah unquestionably are a treasure house of some of the greatest poetry ever written in any language. And even against the stiff competition these chapters get from Amos, Hosea, and Micah, they carry the day. Amos, Hosea, and Micah are all great poets themselves, and their books contain passages that are on literary par with the First Isaiah. But he is more consistent in the overwhelming power that is generated by an imagination expressing itself through compressed verses that somehow keep escaping the bounds of their incredible brevity and exploding into spectacular flashes of light that blind the eyes with their brilliance and sear the mind and the soul with their heat.
At the same time, the First Isaiah exhibits a special skill and delight in wordplay, in assonance, in metaphor and symbol, in unexpected turns of phrase, in bold alterations of meter, and in shifts of tone from the reverential to the sarcastic. Not surprisingly, many of his phrases have infiltrated common discourse ("...let us eat and drink; for to morrow we shall die";"...LORD, how long?...";"...Watchman, what of the night?";"...and a little child shall lead them"; and on and on and on).
Would aesthetic considerations have kept the Book of Isaiah, and the prophetic literature of which it is a part, alive all by themselves? There is no way of knowing. Still, without going so far as William Blake did, critics like Robert Alter and Hillel Halkin, who study the Bible as literature, suspect that such considerations exerted an influence (perhaps unconscious) over the decisions by the rabbis who would shape the biblical canon in the centuries ahead, and who had to determine which of the many candidates for inclusion were divinely inspired and which were not.
The suspicion is heightened by the debates among those rabbis over "The Song of Songs," an erotic poem with no overt religious content that won a place in the Hebrew Bible through being interpreted as an allegory written by King Solomon of God's love for Israel (for which Christians later substituted Christ's love for the Church). Toward the end of the first century C.E., Akiva, the leading rabbi of his generation, suppressed the doubts that had been voiced by his colleagues about the sanctity of the book by exclaiming: "For all the world is not worthy as the day on which the Song of Songs was given to Israel, for all the Writings are holy, but the Song of Songs is the Holy of Holies." The overstatement is a giveaway: Akiva adored this book so much that he would go to practically any hyperbolic lengths to make sure that it was preserved.
For all that, I doubt that it was primarily for its poetry that the Book of Isaiah achieved its reputation as the "supreme" volume in the whole of prophetic literature. The main factor, I would say, was that his book lent itself even better than those of the other prophets of the eighth century B.C.E. to the purposes of the same amalgam of groups we have already run across twice before (both Jewish and Christian), and ex-believers (also both Jewish and Christian) who credited the classical prophets with the invention or the purification of monotheism, or were unwilling or unable to throw out the Bible with the bathwater of faith. True, and as we have seen, the aims of this group could be and were served both by Amos and Micah (though not by Hosea to anything like the same degree). But Isaiah, a longer and richer book, was even more useful.
The net result of the activities of all these groups, to put it bluntly, was that the Book of Isaiah earned its special reputation on false premises. To be sure, the false premises are not its own. They are, rather, the ones imposed on it first by Christians who misinterpreted key passages by reading meanings into those passages that were not there, and then by "enlightened" readers who picked and chose what pleased their sensibilities and ignored what seemed offensive to them.