According to literary scholar James Perrin Warren, Whitman's long, musical lines rely on three important techniques—syntactic parallelism, repetition, and cataloguing. Repetition is a device used by an orator or poet to lend persuasive emphasis to the sentiment, and "create a driving rhythm by the recurrence of the same sound, it can also intensify the emotion of the poem". It is described as a form of parallelism that resembles a litany. To achieve these techniques, Whitman employs many literary and rhetorical devices common to classical poetry and to the pastoral elegy to frame his emotional response. According to Warren, Whitman "uses "anaphora", the repetition of a word or phrase at the beginning of lines; "epistrophe", the repetition of the same words or phrase at the end of lines, and "symploce" (the combined use of "anaphora" and "epistrophe"), the repetition of both initial and terminal words.