Answer:
In the above lines, the speaker metaphorically compares himself to the evening of the day.
Explanation:
William Shakespeare's "Sonnet 73 - That Time of The Year Thou Mayst In Me Behold", he talks of his old age and the subsequent fading or death that is bound to happen. He is using metaphors to characterize the nature of what he perceives to be his old age. His aging s like "the twilight of such day / As after sunset fadeth in the west, / Which by and by black night doth take away," which he likens to "death's second self". The speaker is referring to his growing old age which is like the evening that will eventually lead to darkness, night that is his death.