And out again I curve and flow
To join the brimming river,
For men may come and men may go,
But I go on for ever.

This excerpt from "The Brook" encapsulates the poem's central theme: the relentless passage of time and the enduring nature of the natural world, as opposed to the fleeting lives of humans. In this stanza, the brook personifies itself, emphasizing its eternal and unchanging presence. The line "For men may come and men may go, / But I go on for ever" serves as a poignant reminder of the transitory nature of human existence. Lawrence Aylmer's melancholic reflection on his brother Edmund's untimely death underscores this contrast between the ephemeral human life and the brook's perpetual journey. While people like Edmund live and die, leaving their mark for only a brief moment, the brook continues its journey, indifferent to the individual destinies of those who pause by its banks. This serves to highlight the enduring, indifferent continuity of nature against the backdrop of human mortality.