From Flannery O’Connor's Mystery and Manners:
When you can state the theme of a story, when you can separate it from the story itself, then you can be sure the story is not a very good one. The meaning of a story has to be embodied in it, has to be made concrete in it. A story is a way to say something that can’t be said any other way, and it takes every word in the story to say what the meaning is. You tell a story because a statement would be inadequate. When anybody asks what a story is about, the only proper thing is to tell him to read the story. The meaning of fiction is not abstract meaning but experienced meaning.