Narrative, according to Rasley, presents the particular voice and viewpoint -- usually first-person or third-person -- of a narrator outside the story or a character within it. For instance, Steinbeck's "Of Mice and Men" has a narrator outside the action whose voice has no effect on the plot. By contrast, Ernest Hemingway's "The Sun Also Rises" is narrated by its lead character, Jake Barnes, and F. Scott Fitzgerald's "The Great Gatsby" is narrated by Nick Garroway, a peripheral character. Thus a novel's "voice" achieves different perspectives, and in each story the narrator takes on a different role.
Stephen King in "On Writing" expounds on dialogue's purpose, to give voice to the "cast" of characters in a novel. This achieves two effects: one, the dialogue directly tells the reader about a character based on his speech; two, a character reveals himself/herself through dialogue that contradicts their actions. In Cormac McCarthy's "Blood Meridian," the Judge speaks of war, bloodshed and horror with facile bluntness; he is scrupulously honest about the effects of violence. In William Faulkner's "As I Lay Dying," hardly an honest word passes anyone's lips, but their actions speak for themselves.
It is the combination of narration and dialogue that sometimes helps, but other times hinders, narrative momentum. In the Harry Potter novels, the narrator's tone is often charged with breathless suspense, which is matched by the dialogue of the characters. The combination of these hurtles the reader along the storyline as if he were on a roller coaster. By contrast, Ian McEwan's "Atonement" offers a tale of unjust accusation whose narrator, the accuser in the story, proceeds by guilty fits and starts. The dialogue is full of action but the narration is reflective, which increases the suspense for the reader.
Narrative and dialogue's mutual purpose is to tell a story, so it's not surprising that some authors may attempt only one such element in their writing. Hemingway, in "Big Two-Hearted River," has only two lines of dialogue in an otherwise all-narrative tale; Hemingway also created "Hills Like White Elephants," a story comprised entirely of dialogue with only brief narrative interpolations. Whether narrative and dialogue are used separately or together, an author with a story will find a way to tell it.