“Give this message to Hezekiah king of Judah: ‘Do not let your God, in whom you trust, deceive you by saying that Jerusalem will not be delivered into the hand of the king of Assyria.
Rabshakeh, having delivered his message and received no answer (whether he took this silence for a consent or a slight does not appear), left his army before Jerusalem, under the command of the other generals, and went himself to attend the king his master for further orders. He found him besieging Libnah, a city that had revolted from Judah, Kg2 8:22.
Commenting on 2 Kings 19:8-19
Thus shall ye speak to Hezekiah king of Judah, saying, Let not thy God in whom thou trustest deceive thee, saying, Jerusalem shall not be delivered into the hand of the king of Assyria. (g) The closer the wicked are to their destruction, the more they blaspheme.
Let not thy God in whom thou trustest - This letter is nearly the same with the speech delivered by Rab-shakeh. See Kg2 18:29.