“Arise, arise!”
— William Shakespeare, Cymbeline (1611)
Context
In the play's funeral scene for the supposedly dead Imogen (disguised as the boy Fidele), the call to "arise" is one of several incantatory commands that punctuate the elegy. Imogen is, in fact, not dead but drugged, lending the scene a layer of dramatic irony.
How the repetition works
Two iterations of a single imperative compress urgency into the smallest possible utterance. The audience knows what the speakers do not — that the body may yet wake — which charges the doubled "arise" with anticipatory pressure that the characters cannot feel.