This quote comes from Secrets in the Dark. Buechner is into how he’d go about answering someone who wants to hear about his faith.
I would have to talk about the occasional sense I have that life is not just a series of events causing other events as haphazardly as a break shot in pool causes the billiard balls to careen off in all directions but that life has a plot the way a novel has a plot, that events are somehow or other leading somewhere. Whatever your faith may be or my faith may be, it seems to me inseparable from the story of what has happened to us, and that is why I believe that no literary form is better adapted to the subject than the form of fiction.
Faith and fiction both journey forward in time and space and draw their life from the journey, are in fact the journey. Faith and fiction both involve the concrete, the earthen, the particular more than they do the abstract and cerebral. In both, the people you meet along the way, the things that happen, the places–the airport bar, the room where you have your last supper with a friend–count for more than ideas do. Fiction can hold opposites together simultaneously like love and hate, laughter and tears, despair and hope, and so of course does faith, which by its very nature both sees and does not see and whose most characteristic utterance, perhaps, is “Lord, I believe; help thou my unbelief” (Mark 9:24, KJV). Faith and fiction both start once upon a time and are continually changing and growing in mood, intensity, and direction. When faith stops changing and growing, it dies on its feet. So does fiction. And they have more in common than that.