It's been suggested that without the fear of consequence for one's choices (such as an eternity in Hell) that nothing would matter (people would make choices outside of axiom of moral goodness), which leads me to believe that the moral goodness of many is a result of fear of consequence for...
There are religions that teach the tenet to "harm none" is some form or another. Two religions that come to mind are Jainism and Wicca. I'm confident there are more that teach this tenet to varying degrees.
I think we can agree that the vast majority of humankind has the morality to not kill...