Two of the primary poetic devices that William Shakespeare uses in Sonnet 4 are personification and apostrophe. “Loveliness” is the object of the poem, to whom the speaker directs their remarks. Loveliness is personified: an abstract concept is endowed with human characteristics. Throughout, he also employs apostrophe, direct address to a person, place or concept. This means that the speaker uses second person (“you” or “thou”).
Another main device that Shakespeare uses is the rhetorical question, as the speaker asks loveliness why they do specific things. In doing so, he also employs anaphora, a type of repetition using the same word or phrase at the beginning of sentences or clauses: “why dost thou” appears as the beginning of questions that continue with “spend,” “abuse,” and “use.”
The overall tone of the sonnet is humorously ironic. In addressing loveliness rather than a specific lovely person, the speaker clearly creates an impossible situation: loveliness cannot actually answer them. The rhetorical questions add to this impression, as the speaker asks loveliness why they are selfish and stingy with the beauty that is just lent to them. The speaker also emphasizes the contradictory positions with an oxymoron, or juxtaposition of opposites: “Profitless usurer.” Usurer is also part of a longer metaphor, or conceit, of financial terms, contrasting gifts and loans, with terms such as “unthrifty,” “bequest,” “sums,” “audit,” and “executor.”