The speaker addresses his listener and suggests that he, the speaker, resembles a certain time of year, when elements of nature wither, dry up, and decay (the time of year indicated is autumn or the fall). He compares himself to a sunset taken away by the night, indicating the process of aging. He expands on this theme through mentioning the ashes of youth and their expiration on a deathbed. He exclaims that the listener perceives these processes and it makes his/her love stronger towards that which he/she must leave or lose shortly. The departure strictly indicates youth itself.
The personification of a yearly season in the speaker is a dramatic and powerful image. His elegant description of fall nicely corresponds with the travails of age, and the correlation is attractive and grand. Shakespeare goes on to personify the onset of the night as that which takes the daylight or in this matter youth away. This is easily recognizable by the reader as it recalls the eternal cycle. In life, we are born, reach our childhood, adolescence, and youth. We then reach our middle years, senior years and begin to near extinction, a state that will resemble the time shortly after birth. Similarly, the early morning disperses night, becomes the afternoon, and dawns into the beginning state of a dark night.
Shakespeare’s stylish symbolism is very apparent in the lines describing the speaker lying on the ashes of his youth, as if ravaged by fire, which in this sense parallels the process of life. This is a beautiful concept and is elaborated with the lines describing the nourishment of life, or in association, the fuel which fire provides as the same cause, which will eventually drain and lead to a steady demise.
Shakespeare mentions the word death only twice in this sonnet, and both times it refers to the death of youth rather than the death of the person. At first reading, this can be somewhat misread as our associations might place the somber tone, and grave words as an indication of someone sick uttering their last words. At a closer reading, it becomes clear that the speaker understands the listener’s awareness of his state and knows that the listener has a stronger love for his own youth and treasures it even more knowing it will one day disappear as in the case of the speaker.