There were two grounds, and two only, on which Hezekiah could rest his refusal to surrender,
(1) ability to resist by his own natural military strength and that of his allies; and
(2) expectation based upon the language of Isaiah Isaiah 30:31; Isaiah 31:4-9, of supernatural assistance from Yahweh.
The Rab-shakeh argues that both grounds of confidence are equally fallacious.