己所不欲，勿施於人。
(What you do not wish for yourself, do not do to others.)

子貢問曰：“有一言而可以終身行之者乎”？子曰：“其恕乎！己所不欲、勿施於人。”
(Zi Gong asked: “Is there any word that could guide a person throughout life?”
The Master said: “How about reciprocity! Never impose on others what you would not choose for yourself.”)