John Calvin Commentary Isaiah 36:9

"How then canst thou turn away the face of one captain of the least of my master`s servants, and put thy trust on Egypt for chariots and for horsemen?" — Isaiah 36:9 (ASV)

And how do you despise? He confirms the preceding statement and shows that Hezekiah is so far from being able to endure the presence of his king, that he ought not to be compared to the very smallest of his captains.

In this insolent manner he taunts him, so that the Jews may not derive courage from the absence of Sennacherib, who was still detained by the siege of Lachish.

Therefore, although Sennacherib does not yet appear before them with his whole army, Rabshakeh boasts that his lieutenants are sufficiently powerful, so that Hezekiah ought not to hesitate to make submission.