Let Romeo hence in haste,
Else, when he’s found, that hour is his last.
Bear hence this body and attend our will:
Mercy but murders, pardoning those that kill.
– William Shakespeare
Romeo and Juliet, Act 3, Scene 1. Prince Escalus warns Romeo to remove himself from Verona following his exile from the city. His punishment if he returns there is death. He says that showing mercy to murderers only leads to more murders.