以其人之道，还治其人之身
Traditional: 以其人之道，還治其人之身
English Meaning
- to use an opponent's own methods to obtain retribution (idiom, from Song dynasty neo-Confucianist Zhu Xi 朱熹[Zhu1 Xi1])
- to get revenge by playing somebody back at his own game; to give somebody a taste of his own medicine
