Isaiah’s account of Sennacherib’s siege of Jerusalem is organized in a neat chiasm:

A. Sennacherib’s invasion and the Rabshakeh’s message, 26:1-22

B. Hezekiah goes to temple, Isaiah prophesies, 37:1-7

A’/C. The Rabshakeh’s boast is repeated in a letter, 37:8-13

B’. Hezekiah goes to temple, Isaiah prophesies, 37:14-35

A’. Sennacherib driven from the land, 37:36-38

The structure highlights the fact that the turning point of the story is the Rabshakeh’s decision to record his boast against Yahweh in writing. Jerusalem’s deliverance depends on Hezekiah’s response to the blasphemy; but Jerusalem’s deliverance depends even more on the blasphemy itself. As Yahweh says at the climax of Isaiah’s second prophecy, “I will defend this city to save it for My own sake and for My servant David’s sake” (37:35). As soon as the Rabshakeh puts his boast in written form, the salvation of Jerusalem and the Davidic kingdom is assured.

Chapter 36 itself has a chiastic or alternating structure.

A. Sennacherib invades, and Hezekiah sends Eliakim, Shebna, and Joah as a delegation to the Rabshakeh, 36:1-3

B. The Rabshakeh’s warnings about trusting Egypt and Yahweh, 36:4-10

A’/C. Eliakim, Shebna, and Joah respond, 36:11-12

B’. The Rabshakeh offers a promised land to the men on the wall, 36:13-20

A’. Eliakim, Shebna, and Hilkiah return to the king in mourning, 36:21-22