Two biggest commandments according to Jesus are "Love God with all your hearth and soul" and "Love your neighbor as yourself". The part with loving your neighbor is likely a translation of the golden rule, do unto others as they would have done unto you. So basically dont be a jerk to people for random reasons because how would you feel if that happend to you?
Or i atleast feel you should atleast do stuff you do as you would like to be done unto you in terms of loving yourself. I think common sense is the answer to what you would not like others to have done unto you. Seems to be a legit thing to use.