How do you know if the next act you are about to do is the...

How do you know if the next act you are about to do is the right one or the wrong one? Consider the face of the poorest and most vulnerable human being that you have ever chanced upon, and ask yourself if the act that you contemplate will be of benefit to that person; and if it will be, it's the right thing to do, and if not, rethink it.