Wherefore; rather, but. The final result shall be such as "the Assyrian" little expected. When the Lord hath performed his whole work. The "work" assigned to Assyria was the destruction of the kingdom of Israel, and a share in the trial, punishment, and discipline of Judah.
The last task seems to have been the humiliation of Manasseh, which brought about his repentance (2 Chronicles 33:11-13). Soon after this the troubles began which led to her destruction. I will punish.
The sudden change from the third to the first person is harsh and abnormal, but not without parallels in other passages of Isaiah (see Isaiah 3:1-4; Isaiah 5:3, Isaiah 5:4, etc.). The fruit of the stout heart; i.
e. the actions, language, etc; which flowed from the stoutness of heart—such language, e.g; as that of verses 8-11 and 13, 14. Of the King of Assyria. The menace is not leveled against any one particular king, as Sargon, or Sennacherib; but against the monarchy itself, which from first to last was actuated by the same spirit, and breathed the same tone, of pride, selfishness, and cruelty.
(See the royal inscriptions, passim, which become more revolting as time goes on.