In the sonnet, the speaker asks whether he should compare the young man to a summer's day, but notes that the young man has qualities that surpass a summer's day. He also notes the qualities of a summer day are subject to change and will eventually diminish. The speaker then states that the young man will live forever in the lines of the poem, as long as it can be read. There is an irony being expressed in this sonnet: it is not the actual young man who will be eternalized, but the description of him contained in the poem, and the poem contains scant or no description of the young man, but instead contains vivid and lasting descriptions of a summer day; which the young man is supposed to outlive.