וְגַנּוֹתִ֛י עַל־הָעִ֥יר הַזֹּ֖את לְהֽוֹשִׁיעָ֑הּ לְמַֽעֲנִ֔י וּלְמַ֖עַן דָּוִ֥ד עַבְדִּֽי׃ (ס)
For I will defend this city to save it, for Mine own sake, and for My servant David’s sake.’
Mesilat Yesharim
Likewise Chizkiyahu said: "to peace it is bitterness for me" (Isaiah 38:17) since the Holy One, blessed be He, answered him: "I will defend this city to save it, for My sake and for the sake of My servant David" (Isaiah 37:35). This is as the statement of our sages: "whoever makes his request depend on his own merit, is shown that it was dependent on the merit of others" (Berachot 10b).
Mesilat Yesharim
What will he answer? What will he reply to this rebuke? Behold, certainly if for one moment, a person were to visualize in his mind this truth with a true and strong picture, all of his arrogance would blast off in flight, never to return.