That’s why you should do unto others as you would have them do unto you, Mr. Golden Rule Follower.
That’s why you should love your neighbor as yourself, Mr. Christian.
That’s why what is hurtful to yourself do not to your fellow man, Mr. Jew.
That’s why you should reject for others what you would reject for yourself, Mr. Islam.
That’s why you should hurt not others which pains yourself, Mr. Buddhist.
That’s why what you do not yourself desire, do not put before others, Mr. Confucius.
That’s why you treat others, as thou wouldst thyself be treated, Mr. Hindu.
That’s why you should regard your neighbor’s loss as your own loss, even as though you were in their place, Mr. Taoist.
That’s why you should ascribe not to any soul which thou wouldst not have ascribed to thee, Mr. Baha’i.

Because everyone you meet, is really just you, looking in a mirror.