However, he means not so, neither does his heart think so; but it is in his heart to destroy and cut off nations not a few.…
The significance of ver. 9 appears when the dates of the events alluded to are considered...The application to Jerusalem is obvious...It is true the conquests alluded to in vers. 9-11 are not those of Sennacherib, and vers. 13, etc., would be in his mouth an exaggeration; and hence the prophecy has been referred by some to the period of Sargon. But the subject in vers. 7-11 is "Assyria" (see ver. 5), and though Isaiah may have regarded the king (ver. 12) as being here the speaker, yet vers. 5, etc., show that he speaks, not with reference to his personal achievements, but as an impersonation of the policy of his nation. And this policy Sennacherib in 701 was truly maintaining. The language of these verses does not, therefore, in reality militate against a date which in other respects is in entire accordance with the contents of the prophecy.
(Prof. S. R. Driver, D. D.)
Parallel VersesKJV: Howbeit he meaneth not so, neither doth his heart think so; but it is in his heart to destroy and cut off nations not a few.