Ethic rules, do we need to be told?

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Jesus Christ: Do unto others as you would have them do unto you;
Confucian: if something you do not want people do to you, do not do to people (己所不欲，勿施于人)
This is absolutely what I follow for my life. But, my question is: do we really need to be told to know this “golden rule”?
Honestly, I understood this principle before I read it from these masters, or, “god”, if you prefer.

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