This sonnet explores the tremendous beauty of the object of Shakespeare's affection. The speaker chooses to emphasise his beloved's beauty through personifying nature as a woman in her own right who has selected his beloved and made him more beautiful through her additions to his physical appearance. Note how the beloved's face is with "Nature's own hand painted," and later on in the sonnet, Nature is described as having formed the speaker's beloved:
Till Nature, as she wrought thee, fell a-doting,
And by addition me of thee defeated,
By adding one thing to my purpose nothing.
The personification of nature therefore in this poem depicts her as some kind of female goddess who has the power to bestow and add beauty on to her creations as she desires. Nature is therefore seen as some divine force that controls the appearance of her creations, and clearly, in the opinion of the speaker, she has gifted his beloved with extra beauty, and herself succumbed to the beauty of her work, as the quote states that she "fell a-doting" on the speaker's beloved just as surely as the speaker did himself.