Mercy can refer both to a compassionate behavior on the part of those in power ( for example , mercy shown by a judge toward a criminal by not punishing them as much as they might be punished ) or on the part of a compassionate third party ( e.g. a trip out of mercy trying to treat sick children in Africa ) . The word is very common in several religions ( for example , the mercy of God ) . Mercy ( Middle English , from Anglo-French merci , from Medieval Latin merced - , merces , from Latin , `` price paid , wages '' , from merc - , merxi `` merchandise '' ) can refer both to compassionate behavior on the part of those in power ( e.g. mercy shown by a judge toward a convict ) , on the part of a humanitarian third party ( e.g. a mission of mercy aiming to treat war victims ) or divine mercy shown to the penitent .