William Shakespeare’s "Sonnet 5" eloquently describes the situation of aging, using nature’s seasons of summer and winter as metaphors for youth and old age. Addressing an unnamed youth, the poet laments the fact that "Those hours that with gentle work did frame" the youth’s "lovely gaze" then go on to "play the tyrants to the very same" by undoing their work and bringing on the process of aging. Time is gentle in one season of life, but unkind in another. Note that in Greek mythology, the Hours (Horae) are goddesses who reign over the seasons. They appear in the sonnet as personifications of time.
Aging happens in humans as inevitably as the seasons change. "For never-resting time leads summer on / To hideous winter and confounds him there." (In Shakespeare’s time, winter was sometimes depicted in drawings as a very ugly hag dressed in rags.) The wintertime of life metaphorically freezes life-giving forces ("Sap checked with frost") and keeps them from flowing. There is, however, a way to save the essence of summer.
The rhymed couplet that makes up the final two lines of the sonnet offers a way to overcome time’s inevitable decay: "But flowers distill’d, though they with winter meet / Leese but their show; their substance still lives sweet." The flowers of summer can be distilled and made into a perfume that outlasts the season, though the flowers themselves disappear. This couplet may be a metaphor which suggests that by procreating, the youth to whom the sonnet is addressed can ensure that the essence of life is preserved and passed on.