Final answer:
The author's message in a sonnet's concluding lines often reflects the core theme or presents a volta, with the rhyme pattern playing a crucial role in structuring this shift.
Step-by-step explanation:
The author's message in the last six lines of a sonnet can often encapsulate the theme or provide a twist known as a volta. When analyzing John Keats's "Ode on a Grecian Urn," for example, the ending two lines can be quite profound, with the urn itself possibly delivering the lines "Beauty is truth, truth beauty," suggesting a philosophical standpoint where the aesthetic and the true are inseparable. However, this interpretation can differ based on one's reading of whether it is the urn or the narrator speaking.
The rhyme pattern of a sonnet is essential to its structure, as seen in the task's reference to an octet with an A B B A-A B B A scheme, followed by a sextet with variable patterns. The change in rhyme scheme typically accompanies a shift in the poem's focus or mood, underscoring the volta between the stanzas.