( saying ) used to say that if sb does sth bad to you, the situation will not be improved by doing sth bad to them
TWO WRONGS DON'T MAKE A RIGHT
Meaning of TWO WRONGS DON'T MAKE A RIGHT in English
Oxford Advanced Learner's English Dictionary. Оксфордский английский словарь для изучающик язык на продвинутом уровне. 2005