Isaiah 36–39 is a coherent literary unity that both holds priority over II Kings 18–20 and
reflects a historically reliable interpretation of the events surrounding Sennacherib’s invasion. On a literary level, Isaiah 36–39 shows itself to be a vital piece of the overall literary structure of Proto-Isaiah in that it highlights the fulfilment of Isaiah’s initial Immanuel prophecy in chapters 7–12. The historical occasion for the writing of Isaiah 36–39 is early on during the reign of Manasseh, when opinion in Judah would have been divided over how to interpret the historical events surrounding Sennacherib’s invasion. Isaiah 36–39, therefore, sought to vindicate Hezekiah as a faithful and righteous king, Isaiah as a true prophet and YHWH as the one true God, in contrast to Manasseh’s policy changes that clearly reflected his opinion that Hezekiah was a foolish king, Isaiah was a false prophet and YHWH was not powerful enough to protect Judah.