Milton has an unmatched ability to weave poetic structure with theme and meaning, making the way the poem is put together part of the meaning of the poem. For new readers, this may mean a frustrating bout of learning poetic terms and traditions. However, once a few of the basics are internalized, one begins to realize how the work of Milton has assumed its place, alone, at the top of the canon. He infused the new and unformed English language with a power and depth that his contemporary readers never dreamed it could possess and that poets of succeeding generations have continually aspired to equal.

In the octave, Milton praises Cromwell for his past achievements. With “matchless Fortitude,” Cromwell, “our chief of men,” has triumphantly led his country through war and political turmoil. Milton praises Cromwell’s military victories at the Battle of Preston on the banks of “Darwen stream” at Dunbar and Worcester. Through every obstacle, Cromwell has plowed his way to “peace and truth.” In these seemingly tossed-off lines, Milton alludes to commonly known context. According to Merritt Hughes, the figures of “Peace” and “Truth” were impressed on a commemorative coin issued by Parliament in honor of Cromwell’s victories at Preston, Dunbar, and Worcester. Readers of Milton’s time, upon first hearing the sonnet, could little anticipate that this lilting, seemingly innocent sonnet filled with happy thoughts could turn into a scathing condemnation of their most cherished institutions.

The enjambment that destroys the separation of the octave and sestet (“yet much remains/ To conquer still”) also aborts the homily, cutting short its natural completion with a note of warning. The Puritans have won a kingdom, but will they lose their conscience? Milton urges Cromwell not to rest on his achievements: England has internal enemies of its soul more insidious than any of the external enemies that had threatened its borders. The challenges of wise government call for a valor equal to the battlefield: “peace hath her victories/ No less renown’d than war.” Cromwell has an opportunity to rise up to a still greater glory by defending England’s freedoms of religious tolerance from its homegrown predators.

The poem’s final couplet conflates several well-known biblical references to wolves threatening sheep (for example, John 10:13, Matthew 7:15, and Acts 20:29) that could hardly have been misunderstood by the Puritan ministers targeted by the poet. The portrait of clergy as hireling wolves using the gospel for fangs to tear and rend the very flesh of England is introduced to the reader’s ears by the dissonant line 14 that, of necessity, must be read with unnatural stress and emphasis. The final couplet, the only couplet to end any of Milton’s sonnets, adds audible bestiality to the scenario with the ugly rhyme of “paw” and “maw.” The poet had used the sheep and wolf images before. The ministers under condemnation in Sonnet XVI who were familiar with Milton’s poetry might have recognized echoes from “Lycidas” and have been doubly incensed. In this earlier poem, Satan is the “prowling wolf” who leaps over the fence and into the fold. The sheep are successfully defended from external danger but subsequently die of an internal rot while their inattentive shepherds play loud and lively music.