Curse not the king, no not even in your thought; and curse not the rich in your bedchamber: for a bird of the air shall carry the voice, and that which has wings shall tell the matter.
All Commentaries on Ecclesiastes 10:20 Go To Ecclesiastes 10
Didymus the Blind
Generally one is advised not to say bad things about others. A curse is nothing else but a wish for something bad.…The word cautions against slander. Do not even have the intention, he says, of slandering someone—let alone actually slandering someone. Look at how great an evil this is: “Do not love speaking ill [of anyone], lest you be cut off.” Thus, he says the following: Not even in your thoughts, not even in your consciousness, should you “curse the king.” But if one is not supposed to curse anyone, the king should be cursed even less.