My tears begin to take his part so much
They’ll mar my counterfeiting.

– William Shakespeare

King Lear, Act 3, Scene 6. Edgar nearly blows his cover as Poor Tom when he breaks down in tears in pity for Lear’s insanity and it almost ruins Edgar’s disguise. Lear is acting crazy by setting up an imaginery court to put daughters Goneril and Regan on trial. Edgar feels great compassion for the suffering Lear over the injustice done to him.