John Gill Commentary Isaiah 36:14

"Thus saith the king, Let not Hezekiah deceive you; for he will not be able to deliver you:" — Isaiah 36:14 (ASV)

Thus says the king The king of Assyria, whom he personated, whose general and ambassador he was; so he spoke to command the greater awe of the people, and the more to terrify them:

let not Hezekiah deceive you; for he shall not be able to deliver you;

but if he was not, his God, whom he served, and in whom he trusted, was able to deliver them, and did deliver them; though he endeavoured to dissuade them from trusting in him, or hearkening to Hezekiah's persuasions thereunto, as in the following verse.