"What a man dislikes in his superiors, let him not display in the treatment of his inferiors; what he dislikes in inferiors, let him not display in the service of his superiors; what he hates in those who are before him, let him not therewith precede those who are behind him; what he hates in those who are behind him, let him not therewith follow those who are before him; what he hates to receive on the right, let him not bestow on the left; what he hates to receive on the left, let him not bestow on the right : - this is what is called The principle with which, as with a measuring-square, to regulate one's conduct."
The Great Learning 10.2
"Tzu-kung asked, Is there a single word which can be a guide to conduct throughout one's life? The Master said, It is perhaps the word shu [reciprocity]. What you don't want yourself, don't do to others."
Confucius (551-479 BC), Analects 15:23-24
"One should not behave towards others in a way which is disagreeable to oneself."