Although the poet begs time not to ravish the young man's beauty, to leave it "untainted" as an example of perfection ("beauty's pattern") upon which all can gaze, the concluding couplet, especially line 13's beginning "Yet," underscores the poet's insecurity of what he asks for. However, nature's threatening the youth's beauty does not matter, for the poet confidently asserts that the youth will gain immortality as the subject of the sonnets. Because poetry, according to the poet, is eternal, it only stands to reason that his poetry about the young man will ensure the youth's immortality. The youth as the physical subject of the sonnets will age and eventually die, but in the sonnets themselves he will remain young and beautiful.