Shakespeare's Sonnet 18

In "Sonnet 18," Shakespeare shows his audience that his love will be preserved through his "eternal lines" of poetry by comparing his love and poetry with a summer's day. Shakespeare then uses personification to emphasize these comparisons and make his theme clearer to his audience. Shakespeare also uses repetition of single words and ideas throughout the sonnet in order to stress the theme that his love and poetry are eternal, unlike other aspects of the natural world. Using the devices of metaphor, personification, repetition, and progression of tone, Shakespeare reveals his theme that the natural world is imperfect and transitory while his love is made eternal through his lines of poetry.
Shakespeare uses metaphors to show one object or idea having the same qualities as another. For example, he introduces metaphor within the first line of the sonnet when he asks the rhetorical question, "Shall I compare thee to a summer's day?" Shakespeare uses this as a comparison because a "summer's day" is something with incredible beauty but is still not as beautiful as Shakespeare's love. The fact that Shakespeare chose to compare his love to a summer's day and not a day of another season helps to emphasize the eternity of his love and his poems. During the summer, the days are longer than in any other season. Even still, Shakespeare's love lasts longer than a summer's day. Furthermore, Shakespeare compares the "eye of heaven" having its "gold complexion dimmed" to the setting of the sun. He uses the human characteristic of "complexion" and the sun setting in nature to show his idea that all things in nature advance and grow old over time and, as the sun sets and the summer day ends, the "gold complexion" is "dimmed" and progresses further into decay. Next, Shakespeare compares a human life to the summer's day when he speaks about "thy eternal summer." This emphasizes again Shakespeare's idea that his love is "eternal," unlike other natural things that age and decay. When