When it came to the book of Isaiah, higher critics began by dividing it into two parts. Chapters 1 through 39 were held to be a stylistic unity, while chapters 40 through 66 were said to be written by another man and hence came to be termed Deutero-Isaiah ("second Isaiah"). In time, others further subdivided the text so that, in the opinion of many scholars, Isaiah was actually written by four, five or men individuals in ancient times.

A number of subsequent studies have refuted the idea of multiple authorship for Isaiah. Some of these have been computer-assisted and all have used the Hebrew style of the book as a basis for their judgment on the matter. It is not out intention to depart from our main subject by discussing the pros and cons of higher criticism and those who refute it in the case of Isaiah. We shall be content to point out that one of the main reasons for the attempts to subdivide Isaiah is that the scholars involved simply did not believe in the principle of divine revelation and prophecy. In Isaiah 44:28 and 45:1, for example, we read of Cyrus of Persia, who did not rise to power until about 150 years after the time of Isaiah. For those who cannot believe God can reveal the future to his prophets, these passages appear to be a serious anachronism, explainable only in terms of prophecies written ex post facto by someone other than Isaiah several generations later. Thus, the higher critic has tended to be biased from the beginning by his lack of belief in prophecy.