Tzu-Kung asked saying, Is there any single saying that one can act upon all day and every day? The Master said, Perhaps the saying about consideration: ‘Never do to others what you would not like them to do to you.’ Analects, 15.23, translated by Arthur Waley.
Whatever is hateful unto thee, do not do unto thy fellow: this is the whole Torah; the rest is explanation.
Hillel, Saying of the Fathers, translated by Rabbi Joseph Hertz.
Religion is the definition of man’s relationship to the origin of everything, and of the purpose acquired as a result of this relationship, and of the rules of conduct that follow from this purpose. And the religion common to all, the basic principles of which are alike in all practices, fully satisfies these demands. It defines man’s relationship to God as of a part to a whole. From this relationship follows man’s purpose, which lies in increasing his spiritual qualities, and man’s purpose leads to the practical rules of the law: do to others as you would have them do unto you.
Leo Tolstoy, What Is Religion and of What Does It Consist?, translated by Jane Kentish.