Like as the waves make towards the pebbled shore / So do our minutes hasten to their end;"
Like waves moving toward the pebbled shore, the minutes of our lives are ticking down,
"Each changing place with that which goes before / In sequent toil all forwards do contend."
Each minute (or wave) replacing the previous one, in a continuous forward march.
"Nativity, once in the main of light / Crawls to maturity, wherewith being crown'd,"
The newborn sun rises above the sea and crawls up to maturity (noontime), where it is kingly,
"Crooked eclipses 'gainst his glory fight / And Time that gave doth now his gift confound."
But slanting eclipses challenge the sun's glory, and Time, which gave the noon sun, now clouds it over.
"Time doth transfix the flourish set on youth / And delves the parallels in beauty's brow,"
Similarly, time destroys the perfection of youth, and carves wrinkles in a beautiful face,
"Feeds on the rarities of nature's truth / And nothing stands but for his scythe to mow:"
And time feeds on the preciousness of nature's perfection, and lays waste to all in its path.
"And yet to times in hope my verse shall stand / Praising thy worth, despite his cruel hand."
And yet I hope my verse will stand the test of time, praising your worth in spite of Time's cruel hand.
In the sonnet, time is symbolized by concrete images. For example, the opening two lines present a simile in which time is represented by "waves" and "minutes": "Like as the waves make towards the pebbled shore, / So do our minutes hasten to their end"; here, death is "the pebbled shore" — another concrete image.
In the second quatrain, the poet laments time's unfairness. A child — "Nativity" — is born and, over time, matures to adulthood, and yet the adult now dreads the maturation process as he grows increasingly older and thus reaches the point of death, or the end of time. Time, which gives life, now takes it away: "And Time that gave doth now his gift confound."
The antithesis in lines 9 through 12 is between the aging poet and the youth's good looks. The poet warns, "Time doth transfix the flourish set on youth / And delves the parallels in beauty's brow." In other words, the young man currently is beautiful, but "parallels" — wrinkles — will eventually appear, as they have on the poet. However much the young man and the poet would like beauty to reside forever on the youth's face, "nothing stands but for his [time's] scythe to mow."
Nonetheless, the poet promises to immortalize the youth's good looks before time's wrinkles appear on his face: "And yet to times in hope my verse shall stand, / Praising thy worth, despite his cruel hand." Unlike the poet's promise in Sonnet 19, this assurance does not include giving the young man eternal beauty. Even more, the "scythe" in line 12 recalls Sonnet 12's concluding couplet: "And nothing 'gainst Time's scythe can make defense / Save breed, to brave him when he takes thee hence." Clearly the poet is no longer concerned that the young man have a child to ensure the immortality of his beauty. Now, the poet's own sonnets are the only security the youth needs to gain eternal worth