In the first of the poem's two stanzas, the speaker declares that a "slumber" has kept him from realizing reality. In essence, he has been in a dream-like state, devoid of any common fears ("human fears"). To the speaker, "she" (his unnamed female love) seemed like she would never age:
A slumber did my spirit seal;
I had no human fears:
She seemed a thing that could not feel
The touch of earthly years.
In the second and final stanza, however, we learn that she has died. She lies still and can no longer see or hear. She has become a part of the day-to-day course of the earth:
No motion has she now, no force:
She neither hears nor sees,
Rolled round in earth's diurnal course
With rocks and stones and trees.
"A slumber did my spirit seal" is one of Wordsworth's "Lucy Poems," which focus primarily on the death of a young woman named Lucy (though she remains unnamed in this poem). Many scholars and literary historians have offered theories as to who Lucy was, but her true identity remains a mystery.
The poem is comprised of only two four-line stanzas, and yet a great deal happens in this narrow space. We see the speaker's realization not only that this young woman has died, but also that bad things can happen in a beautiful world. In the first stanza the speaker is innocently unaware that age can touch the woman, but he is quickly taught a harsh lesson when she dies between stanzas one and two. The choice to hide the death between the stanzas is interesting, as it seems to imply that the speaker is unable to verbalize the pain that goes along with the sudden loss.
On the other hand, the poem may be less about the speaker's innocence than about his belief in the young woman's power. Indeed, he seems to have built her up in his mind into a goddess, untouched by age and mortality. This desire to keep her perpetually young is a testament to the speaker's feelings for the young woman.
In the second stanza Wordsworth offers an eerie description of the woman's current situation. She is blind and deaf--wholly incapable of taking in the world around her. This is a particularly painful idea in a Wordsworth poem, because he is generally so focused on experiencing the senses. The speaker also mentions that she is now without motion or force. This, of course, is true of all dead people, but by stating the obvious the speaker helps the reader to imagine the way the young woman once was: full of life and vigor.
In the last two lines the speaker describes the young woman trapped beneath the surface of the earth. In fact, she has become a part of the earth, rolling with it as it turns day to day. The very last line of the poem is especially interesting, because the speaker lists both rocks and stones, which are essentially the same. It may be that he intends to reference both gravestones and common rocks. Alternatively, the speaker may intend to emphasize the "dead" things of the earth over living things like trees (which are mentioned only once).
"A slumber did my spirit seal" is a ballad, though a very short one. The stanzas follow an abab rhyme scheme, and the first and third lines are in iambic tetrameter, while the second and forth lines are in iambic trimeter.