How malicious is my fortune that I must repent to be just! This is the letter he spoke of, which approves him an intelligent party to the advantages of France. O heavens, that this treason were not, or not I the detector.
– William Shakespeare
King Lear, Act 3, Scene 5. Edmund betrays his father Gloucester and gains Cornwall’s approval by showing him a letter proving Gloucester’s support for an invasion of England by the French. Edmund pretends to be shocked by his father’s "treason" and that he was the one who detected it. But in reality he is very pleased, as Cornwall now makes him Earl of Gloucester. When Edmund says he must repent of being just, he is pretending to be in a difficult moral position where he has to apologize for doing the right thing. Deception comes naturally to Edmund, who cheats and lies to everybody he meets.