A metaphor is a comparison that does not use the words like or as. In Herrick's poem, love is likened to rosebuds or flowers, sweet flowers that will not last long. This metaphor emphasizes that life and love are short and fleeting. If one doesn't pick and enjoy the flowers now, they will be gone.

The sun is compared to a lamp. A day is likened to a race that will soon be over. A lamp goes out and a race ends, so these metaphors too add urgency to the idea that one should live life fully while it is still possible.

This is a classic example of a "carpe diem" poem. Carpe diem means seize the day. These poems are driven by the idea that we will soon grow old and die, so we should seize our joys while we can.

The primary metaphor is "Gather ye rosebuds while ye may." Rosebuds are youth and beauty. This is the theme of the poem, which is "carpe diem" or "seize the day." We only have one life, and one youth. It must be enjoyed while it lasts.

Just as a reminder: a metaphor is "a figure of speech in which an expression is used to refer to something that it does not literally denote in order to suggest a similarity. "