Happy the man, and happy he alone,
He who can call today his own
The speaker presents the poem's central argument: that one must live in the now in order to be truly happy. The alliteration of the “h” sound (“Happy the man, and happy he alone, / He who can call today his own”) creates a breathy and uplifting soundscape for the poem—perhaps reminiscent of the sound of laughing. On the other hand, the voice of the speaker, instructive and matter-of-fact, evokes that of maxims and proverbs. The didactic optimism of the opening lines firmly establishes the tone of the rest of the poem.
Tomorrow do thy worst, for I have lived today
In this apostrophe/personification (in which the speaker treats the abstract notion of the future —“tomorrow”—as a humanlike and conscious entity), the speaker argues that the “happy man,” who is confident about his present (“I have lived today”) does not fear the future no matter how uncertain or threatening it may be (“Tomorrow do thy worst”). Not only does this line both personify and undermine humankind’s universal fear of the future, but it also illustrates the assertive voice of the poem’s hypothetical everyman and his unwavering resolution before the ups and downs of life.
Not heaven itself upon the past has power
This hyperbolic statement emphasizes the poem’s argument that no one—not even a divine entity—can change one’s past, and that one must move on from it. That even “heaven” does not have control over the past is a situational irony that highlights the importance of a mindset that focuses on the present. The repetition of plosives in “upon the past has power” contributes to the strong and assertive tone of this statement.
