B. Repetition
The rhetorical device most prominent as we can see with in the first words of sentences is the repetitive use of “let both sides.” The specific type of repetition here is known as anaphora, which is the repetition of a word (or in this case words) at the beginning of line/verse/sentence. That said, repetition is quite the effective literary device when the desired effect is to emphasize in order to highlight importance.