How does George Herbert use iambic tetrameter and dimeter in “Vertue”?

In the poem "Vertue," George Herbert utilizes a specific stanzaic structure consisting of three lines of iambic tetrameter followed by one line of iambic dimeter. An iambic foot consists of an unstressed syllable followed by a stressed one; thus, the tetrameter lines contain four such units, while the dimeter line contains two.1

This recurring pattern serves as the poem's metrical foundation, though Herbert introduces substitutions—specifically trochees—to create tension between the established metrical pattern and the poem's meaning. For example, in the fifth line, a reversed third foot emphasizes the word "angry," providing semantic reinforcement that generates a powerful surge of feeling. By occasionally disrupting the regular recurrence of the iambic feet, Herbert ensures the metre remains expressive rather than merely mechanical, allowing the technical structure to support the poem's thematic depth.12