Seven lines are all that remain of this stanza, and the title tells us why it feels unfinished: it was "cancelled", struck out of whatever larger work it once belonged to. We can't see that surrounding poem, so the stanza has to stand on its own. It does so as a small, bright vision of reconciliation. Enemies are summoned together, conflict dies away, and even Power, the thing that usually frightens us, turns gentle.
The opening is an invitation, almost a ritual call: "Gather, O gather, / Foeman and friend in love and peace!" The "O" gives the voice a ceremonial, hymn-like pitch, and the repeated verb sounds like a herald calling a crowd. "Foeman" is an old-fashioned word, and it is placed before "friend", as if the enemy is welcomed first. The line makes no distinction between the two, and that is the point. Peace here is not a victory for one side but a meeting place for everyone.
Shelley then turns to nature for his central image: "Waves sleep together / When the blasts that called them to battle, cease." Political conflict becomes weather. The waves don't fight out of their own malice; they are stirred up by winds, "blasts" that "called them to battle". The metaphor suggests that human strife may also be provoked from outside, and that when the provoking force drops away, the violence drops with it. The personification of sleeping waves is gentle and physical. The short, soft line "Waves sleep together" lets the sea settle, and the long vowels and sibilance almost hush the reader. Notice too that the rhymes in this first half, "gather/together" and "peace/cease", enact the meaning: a scattered crowd comes together, and peace is defined by the ceasing of noise.
The last three lines shift from sea to a stranger, more allegorical picture. "Fangless Power grown tame and mild / Is at play with Freedom's fearless child". Power is imagined as a creature that once had teeth, and the word "fangless" is the key to the whole passage. The peace is not achieved because Power has become virtuous, but because it has been defanged. "Grown" suggests a gradual change rather than a sudden one. Against it stands "Freedom's fearless child", and the alliteration of "fangless" and "fearless", along with "Freedom's", links the two sides through sound even as their meanings oppose each other. Only a fearless child could play with something that used to bite.
The closing line, "The dove and the serpent reconciled!", names the creatures at last. Judging by the imagery, Power is the serpent and the child of Freedom the dove, though the stanza never says so outright. The pairing may echo the old biblical contrast between serpents and doves, but here the point is not that one must imitate the other. They are simply reconciled, and the exclamation mark gives the line the force of a triumphant announcement.
The form supports this movement. The stanza runs in a pattern of ABABCCC, and the final three lines share a single rhyme: "mild", "child", "reconciled". After the shorter, lighter opening lines, this triple rhyme works like a chime that rings three times and settles. The lines are uneven in length, with the very short "Gather, O gather," and "Waves sleep together" set against longer lines of about four beats, which gives the stanza a speaking, song-like flexibility rather than a rigid march.
What makes the fragment interesting is the tension between its confidence and its title. It imagines Power losing its fangs, a hope that is easy to state and very hard to realise, and the word "cancelled" hangs over it like a question. We can only guess why it was removed. Still, even cut off from its poem, the stanza is a compact picture of the hope that opponents might meet without fear, and its sounds and images carry that hope persuasively in just seven lines.