the general philosophy of treat others as you would be treated. (Which is the most important lesson in my bibles. IMHO)
I read a comparison of all major religions a few years ago, and this was one of the few common factors of all of those religions. To me though, this is not only something that relates to religion. This is what our parents and teachers taught us from the time we were born. It is about mutual respect, and should be practised by us all.