To demonstrate the theme of impatience the poet begins the poem by quoting the boy when he says "I'm rising five, not four" which also introduces an irony that one so young should measure his life in terms of numbers and look forward to the future when he should have no need to do so. The word "alive" in the first stanza is also an ironic diction that suggests that the boy is more dead than alive. To make the idea of impatience more clear to the reader the poet also uses parallel constructed refrain at the end of each stanza: "not four, but rising five. Not may, but rising June. Not day, but rising night. Not now but rising soon. Not living but rising dead," showing that with impatience death is coming sooner than expected.
To convey the idea that nature like the boy is impatient, rushing quickly for the finish line, to end the season, the poet uses antithetical parallelism: "we never see the flower, But only the fruit in the flower: never the fruit, But only the rot in the fruit." What the boy does not realize is that nature (the seasons and their specialty for example (spring is the season for the flowers to bloom)) never dies but only returns the next year and will return again and again, but after the boy dies he will be gone for ever.
The fact that we stop being human if we reduce life to numbers is conveyed in the seventh line of the first stanza when the poem reads "fifty-six months or perhaps a week more." The poet could have chosen to use the words "four years and eight months," but chose to use the words "fifty-six" to emphasize more on the