Stevenson's poem is only eight lines long, and it spends them on one sharp turn. In the first stanza the speaker remembers planning to sing of love among the flowers. In the second he is shut indoors, thinking about death. The hinge is the word "Now," which opens the second stanza and sets present against past. The central idea is that the hopeful plans of youth, or of any bright season, can be overtaken by a colder and quieter mood. The poem never says why. It simply shows the change.
Notice the verb in the opening line: the speaker "thought to sing" love and the lyre. That is a plan, an intention, and it hints that the singing never quite happened. The pleasures he imagines are reciprocal: "kisses sweet to give and take." Set against that is the stanza's last word, "aloof," which means apart, alone, withdrawn. The poem moves from a shared pleasure to a solitary one.
The two stanzas are built as mirror images, and the poem's force comes from how neatly they match. "Spring" becomes "Autumn." "Love and the lyre" becomes "Death and the grave." "Kisses sweet" turns into "winter drear." The "flowery hawthorn brake," an open, scented thicket, is replaced by "the rain … on the roof," a sound heard from inside, under cover. The colours shift too, from the fresh "green" of the opening line to "russet," the dull reddish-brown of dead leaves. The speaker has moved indoors, from a landscape to a ceiling.
The word choice helps. "Gallant" is a surprising adjective for spring. It suggests something dashing and a little showy, like a young knight, and it matches the poem's old-fashioned vocabulary: "lyre," "brake," "drear." That slightly antique diction gives the first stanza the feel of a conventional love song, the kind a poet is expected to write in spring. The second stanza keeps the same costume but fills it with gloom. Its list, "Death and the grave and winter drear," is stacked with repeated "and"s, so the gloomy ideas pile up one after another. The clipped "drear" sounds like a door closing.
The form is simple and tight. The poem is written in rhymed couplets (spring/sing, take/brake, here/drear, aloof/roof). Each line has four beats, though the feet shift between falling and rising rhythms. "IN the green and GALlant SPRING" starts on a stress, while "And KISSes SWEET to GIVE and TAKE" starts with an unstressed syllable. Line lengths alternate between about seven and eight syllables, which keeps the movement light and song-like. That lightness is part of the effect. The first stanza sounds like a song, but the second, with the same tune, sounds like a song with the joy removed. The couplets also close each idea with a snap, and the last rhyme, "aloof" with "roof," ends on a flat, hollow sound that offers no comfort.
The repeated "here" is easy to miss. Autumn is "here," and the speaker must "ponder here." The second stanza keeps pinning him to one spot, in contrast to the open air of the hawthorn brake. "Must" adds a note of compulsion: he does not choose this brooding, he is made to do it. "Ponder" is a slow, heavy verb, and it is set against the lighter "sing" from the first stanza.
The poem leaves open whether it is about literal seasons or about stages of a life. The imagery of spring and autumn, love and death, invites the second reading, and that is an inference from the text rather than something it states. Either way, the effect is the same. The poem declines to console. It offers no new hope and no lesson, only the steady sound of rain.
The poem's significance lies in this economy. Stevenson is best known for adventure fiction, so a brief, inward lyric like this one shows a quieter side of his writing. In eight lines it takes an old and familiar idea, that seasons pass and moods darken, and makes it personal by anchoring it in a single image: a person sitting still, listening to rain. For a young reader it is a good example of how contrast and repetition can carry a whole emotional journey in very little space.