Gratitude is usually easy to express, but Shelley begins by making it almost impossible. The first four lines are one knotted sentence. Even if tears had not trembled in his eyes, the speaker says, and even if his heart had not beaten fast with feelings "which make rapture pain resemble," he would still thank his friend, because "falsehood starts aghast" at that friend's voice. The syntax is tangled enough that the exact logic is open to debate, but the drift is clear: the speaker is so overcome that his grammar buckles under the feeling. The phrase "rapture pain resemble" captures the state well, since joy at its most intense feels close to hurting. The poem never says who the friend is or why he was imprisoned. The title gives only the bare fact of release, so the poem runs on feeling and principle rather than anecdote.
The friend's voice matters because falsehood personified flinches from it, like a startled animal. Truthfulness is the quality being praised, and it is the very quality a tyrant would want to lock away.
Then the poem turns. After "I thank thee," a dash breaks the sentence, and the lines shorten from the five-beat pattern of the opening to brisker four-beat ones. The rhyme changes too. The opening alternates (tremble / fast / resemble / aghast), but from here the poem moves in couplets: keep / weep, risen / prison, bind / humankind. The effect is a shift from private, halting emotion to something more like a declaration. The speaker stops addressing his friend about himself and begins to address the world about the tyrant.
That tyrant is never named, and he is left with very little. "Let the tyrant keep / His chains and tears" sounds like contempt, as if he were being allowed to hold onto his only possessions. His tears are a pointed echo of the speaker's earlier ones. One man weeps from rapture, the other "with rage," and the power the tyrant imagined he held has turned into helpless grief.
The central image arrives in the simile "freshly risen, / Like strength from slumber, from the prison." Prison becomes sleep, not a grave, and the friend's strength was resting, not broken. The word "risen" also carries a faint suggestion of resurrection. The rhyme helps here. "Prison" lands at the very end of the line, so the confinement is already behind him.
The final two lines hold the poem's boldest idea. The tyrant "vainly hoped the soul to bind," and "vainly" gives the verdict before the sentence is over. The last line then stretches to twelve syllables, longer than anything before it, as though the verse itself were breaking its limits. As I read the inverted syntax, the soul is what "must prey" on the chains, so the roles are reversed. Chains are supposed to hold their victim, but here they become the soul's prey, something to be gnawed through. The closing phrase, "that fetter humankind," widens the view. The chains are no longer only the ones that held one friend but those that bind everyone, and the freed man's spirit becomes a threat to all of them.
The poem is labelled a fragment, and it ends without a full resolution, but it feels strangely complete. In ten lines it moves from a stammer of emotion to a political claim: tyranny can confine a body but cannot hold a mind, and a free voice outlasts the walls built to silence it. It also treats friendship as a form of courage. The speaker's thanks are not just personal but a way of siding with truth against force. Beneath the passion, the poem's logic is cool and exact. The tyrant ends up the real prisoner, locked into rage and unable to prevent what he feared, while the friend, "freshly risen," walks out as the stronger man.