A story in which things represent parts of a doctrine or theme is an allegory.
An allegory is a metaphor in which a character, place or event is employed in order to deliver a broader message about real-world issues and occurrences. Allegory has been used widely throughout history in all forms of art, largely because it can readily depict or convey complex ideas and concepts in ways that are comprehensible or striking to its viewers, readers, or listeners.