We Catholics are very much given to the Instant Answer. Fiction doesn't have any. It leaves us, like Job, with a renewed sense of mystery. St. Gregory wrote that every time the sacred text describes a fact, it reveals a mystery. This is what the ficiton writer, on his lesser level, hopes to do. The danger for the writer who is spurred by a religious view of the world is that he will consider this to be two operations instead of one. He will try to enshrine mystery without the fact, and there will follow further separations inimical to art. Judgment will be separated from vision, nature from grace, and reason from imagination.
These are separations we see in our society and exist in our writing. They are separations which faith tends to heal, if by faith we mean "walking in darkness" and not a theological solution to mystery.
It is when the individual's faith is weak, not when it is strong, that he will be afraid of an honest fictional representation of life; and when there is a tendency to compartmentalize the spiritual and make it resident in a certain type of life only, the supernatural is apt to become lost.
--Mysteries and Manners pg 184 & 151 respectively