Returning to the same word, the same phrase or the same construction, at the beginning of consecutive verses or sentences (anaphora) or throughout the text, to give rhythm, emphasis or insistence.
In Hamlet
The body is with the King, but the King is not with the body.
“Body” and “king” appear twice, in reversed order. The return of the same terms gives the sentence the air of a riddle that Rosencrantz and Guildenstern cannot untangle.
Act IV: Exile, madness, and the trap, Hamlet, to Rosencrantz and Guildenstern