A fading morning star is a small thing to hang a whole elegy on, but Burns does it with confidence. The speaker turns to the "ling'ring star" that "lov'st to greet the early morn" and half-blames it for what it brings: "Again thou usher'st in the day / My Mary from my soul was torn." The word "again" matters, because it suggests a painful day coming round once more. The star's "lessening ray" is also a quiet image of the beloved herself, still at the edge of sight but dissolving as the light grows. "Torn" is a harsh, physical verb, and it finds an echo at the end of the stanza in "groans that rend his breast." Grief is described as a wound twice over.
Those closing lines are also questions, and they are never answered. "Where is thy place of blissful rest? / See'st thou thy lover lowly laid?" The dead woman is addressed as a "shade," and the speaker can only ask whether she can see or hear him. This is the poem's central tension: love reaching toward someone who may not be able to reply. "Lowly laid" is nicely double-edged, since it can mean brought low by sorrow, yet it also leans toward the grave.
The middle stanzas turn to memory, and the mood changes completely. The speaker recalls the "hallow'd grove" by "the winding Ayr," where the couple met "to live one day of parting love." That phrase is a small paradox, because love is lived and lost in the same breath. Then comes the plainest, most devastating line in the poem: "Ah! little thought we 'twas our last!" Burns uses no ornament here. An exclamation and a simple sentence are enough.
The third stanza is the most richly imagined. Nature seems to join in the lovers' happiness. The river "gurgling, kiss'd his pebbled shore," a line that lets us hear the water as well as see it. The birch and hawthorn "'Twin'd amorous round the raptur'd scene," the flowers "sprang wanton to be prest," and the birds "sang love on every spray." Everything is touching, embracing or singing, and the landscape becomes a mirror of desire. Then the stanza closes with a sudden drop in speed: "Till too, too soon, the glowing west, / Proclaim'd the speed of winged day." The doubled "too" sounds like a sigh. It is also worth noticing that the poem opens at dawn and remembers a sunset, so the whole day, and the whole love affair, is held inside the speaker's thoughts.
Formally, the poem is steady and song-like. Each of its four stanzas has eight lines of mostly regular iambic tetrameter, rhymed ABABCDCD, and the plain, even rhythm makes the feeling seem sincere rather than showy. The title calls it a "Song," and the regular stanzas suit that label. The rhymes are mostly full and simple (*ray/day*, *rest/breast*), so the poem rarely strains for effect.
The last stanza brings back the refrain from the first, almost word for word. Only the order shifts, from "place of blissful rest" to "blissful place of rest." The effect is circular. After all the remembering, the speaker is exactly where he started, asking the same unanswered questions. Between these two identical frames, memory is said to "fondly" brood "with miser-care," as if the past were a hoard of coins to be counted over and over. Then comes the poem's finest image: "Time but th' impression stronger makes, / As streams their channels deeper wear." The river that once kissed its shore so playfully returns as a figure for grief. Water does not smooth things over but cuts further down each year, and time does not erase memory but deepens it.
This is why the poem lasts. Burns takes the old consoling idea that time heals and quietly turns it around, using nothing more than a star, a river and a handful of plain words. The poem's pleasure is that its landscape is both a joy remembered and a wound that keeps being reopened.