Mutual indifference of people not willing to help

Here is the core idea. If you do not come to the aid of others who are under grave assault, in acute danger or crying need, you cannot reasonably expect others to come to your aid in similar emergency; you cannot consider them so obligated to you. 

Other people, equally, unmoved by the emergencies of others, cannot reasonably expect to be helped in deep trouble themselves, or consider others obligated to help them  this is the contract of mutual indifference.