It takes one to know one.

彼此彼此
a caustic,biting expression of verbal retaliation know one to someone who had immediately before called the speaker some derogatory name; i.e.,having been called a liar,the speaker responds with:" well,it takes one (a liar) to know one (a liar)"
辛辣的措辞,口头报复刚才说话者的人,例：说话者因被称为说谎的人而报以“彼此彼此”.
So you say that I'm a cheapskate,do you?Well,it takes one to know one!
你说我是个吝啬鬼,是不是?彼此彼此!