Lines 1–2

These lines introduce the poem's central theme, using a metaphor that likens Time to a bird that has flown away with Milton's youth ("stol'n on his wing").

Line 3

In this line, the poet conveys his perception of time's swift passage with phrases like "hasting days" and "full career."

Line 4

The poet employs a seasonal metaphor to describe his stage of life as a "late spring," noting that it has yet to show any "bud or blossom," symbolizing a lack of achievements or potential in his life.

Lines 5–6

The poet observes that his appearance belies his actual age, suggesting that he looks younger than he is ("deceive[s]" the truth that he is nearly a man).

Lines 7–8

The term "inward ripeness" extends the natural metaphor from line 4's "bud" and "blossom." The poet claims to possess more inner maturity than his exterior shows, and more than some of his peers, the "more timely-happy spirits," exhibit. Consider the different interpretations of "endur’th." The lines are grammatically inverted and could be paraphrased as, "and inward ripeness, which imbues or clothes some others, appears less in me." The phrase "timely-happy spirits" might refer to those who are more at ease with their age or whose age more positively reflects their inner self.

Lines 9–12

"It" might refer to the appearance of inward ripeness mentioned in line 7. Regardless of whether this ripeness appears now or later, it will align perfectly with his destiny, the "lot . . . / Toward which Time leads" him. While the octave highlighted a dissonance between his internal and external maturity, the sestet resolves that time and divine will shall harmonize these aspects. Note the multiple puns here: "measure" might mean a musical measure or a line of poetry; "even" might modify "measure" as an adjective or transition into the next line, "even to that same lot." Milton often places adjectives both before and after nouns, and he frequently allows a word at the line's end to serve dual purposes.

Lines 13–14

Critics have debated the exact interpretation of these lines, but generally, they imply that whatever the speaker's life's outcome, it will occur with God's awareness and according to His plan. The "great Task-Master" refers to God.