Do unto others as you would have them to do unto you, for this is the law and the prophets.
A favorite exercise for high school and college teachers is to give their students a moral quandary, e.g., what would you do if by pushing a man in front of a train you would save the lives of all the passengers on the train?
I've lived for a pretty long time here on this earth and I've never had a real life situation where I've had to make such a decision. But every day, many times a day, circumstances put me in situations where I can make a decision, will I look out for my own concerns, or instead, look out for the concerns of others?
To live a life pleasing to our Lord, we need to always keep in our consciousness doing to others as we would have them to do to us.