For mine own sake - God’s honor was concerned to defend His own city against one who denied His power in direct terms, as did Sennacherib 2 Kings 18:35; 2 Kings 19:10-12. His faithfulness was also concerned to keep the promise made to David Psalms 132:12-18.
Related Commentaries of 2 Kings 19:34
2 Kings 19:34
34 For I will defend this city, to save it, for mine own sake, and for my servant David's sake.