Howbeit he meaneth not so, neither doth his heart think so; but it is in his heart to destroy and cut off nations not a few.
Howbeit he meaneth not so - He is only thinking of his own schemes, while God is overruling them to His purposes.
Neither doth his heart think so - intend so. Sinners' plans are no less culpable, though they by them unconsciously fulfill God's designs (Psalms 76:10; Micah 4:12). So Joseph's brethren (Genesis 50:20; Proverbs 16:4). The sinners' motive, not the result (which depends on God), will be the test in judgment.
But (it is) in his heart to destroy and cut off nations not a few. Sennacherib's ambition was not confined to Judea. His plan was also to conquer Egypt and Ethiopia (Isaiah 20:1-6; Isaiah 33:1).