We say "a lesson 'in' something". What is the acceptable preposition to be used with "moral" as a synonymous noun with "message" or "lesson"?
The most common collocation is "the moral 'of' the story," but "of" here conveys the idea that there is a lesson motivating the story, a lesson "behind" the story. I want to use "moral", however, to introduce what the lesson is about. I thought of "a moral 'about' compassion," but apart from that I have never heard that construct before, it sounds to my ear less powerful than "a lesson in compassion."