There are those who ... [think] that the novel is somehow less "real" than a more didactic book. The reality of fiction, however, lies on a deeper plane than mere "factness." Reality is a function of truth. And truth--however conveyed is real....
"Do good to your neighbor" was not a teaching that originated with Jesus; it had been set forth by hundreds of great men before. But it was Jesus who penetrated clearly and incisively to the very heart of the matter with his parables of the Good Samaritan, immortalizing the truth as no one before or since has ever done... Through the nonfactual, but highly real, genre of the parable--of fiction--Jesus brought spiritual principles to life. 

Michael Phillips. Introduction to KNOWING THE HEART OF GOD by George MacDonald.