Shelley's poem argues that parting from someone you love can be worse than dying. The bracketed name in the title marks the addressee as Harriet, though the poem calls her only a "friend" and keeps its circumstances vague. We learn that fate "compels us for aye bid adieu to the land" where the loved one lives, and that is all. The poem is not interested in explaining the separation. It wants to measure how much it hurts, and it does so by setting parting against death and letting death lose.
The comparison builds across the middle stanzas. Parting is "sterner than death," and death is drawn as a king, a figure bending over a "shuddering wretch" with a "skeleton grasp" and a "fell sceptre." That is stock Gothic furniture, but it sets up the twist in the third stanza, where the parted lover "may envy" the wounded animal, the "bleeding and gory" bosom, even "the sound of the drear passing knell." The deer is the poem's one fresh image. It drags itself toward a "loved covert" it will never see again, which makes dying and exile look like the same act, a creature heading for a place it loves, knowing it is the last time. The fourth stanza finishes the argument by comparing the dying man on his "death couch" with the "outcast" who hears the "last tones of thy voice" fading on the wind. The outcast's grief is deeper. The grammar strains here, and the sentence nearly collapses under its own comparisons, but the direction is clear.
The poem's most interesting structure is a contrast between two voices. It begins with the voice of fate, which "breathes" "accents of horror" in our ear. It ends with the beloved's voice, whose tones are "so soft, and so sad" that they cannot stop vibrating "on Memory's ear." One voice commands and the other lingers, and the poem sets the harsh one against the tender one. The word "ear" ties the two together. It appears in the first stanza and returns in the last as "Memory's ear." The poem has moved from hearing a sentence passed to hearing a voice that cannot be silenced. The pronouns shift too. The first three stanzas speak of "us" and "he," and only late does the speaker say "thy," turning from a general lament to a private address.
The sound of the poem works in a similar way. Its rhythm is anapaestic, a galloping beat of two light syllables and then a heavy one. The opening line begins with two heavy stresses, "Stern, stern," and then rolls on with "is the voice of fate's fearful command." The momentum fits the rush of feeling, but it also gives the verse a sing-song lilt that sits strangely beside such heavy grief. The rhyme scheme is unusually insistent. Stanzas two and four each begin with three lines ending in the same sound ("bending," "extending," "wending"; "reposing," "closing," "losing"), and these are exactly the stanzas about death and dying. The triple rhyme works like a tolling bell, and then the fourth line breaks from it with "appear" and "swell." "Farewell" and "knell" also share a rhyme in the third stanza, so parting and the death-bell chime together.
"Stern" is the key word. It opens the poem twice over, becomes "sterner" in the second stanza, and returns in the last line's "stern wreck of Nature." The word starts out describing fate's voice and ends up describing the whole natural world in ruin. Even then, one thing survives: "The remembrance must live of a friend so sincere." The final claim is that memory outlasts the wreck of nature itself.
As a piece of writing, the poem is uneven. Its diction is borrowed and heavy with "ah!", "adieu," "bosom," "aye," and the clustered "-ing" rhymes sometimes seem to dictate the sense rather than follow it. Its value for a student lies elsewhere. It shows how a poet can build an argument out of sound, rhyme and repeated words, and how, in a poem about absence, the strongest thing left is a voice heard in the mind.