An overemphasis on rights leads to a disregard for duties. Duties set a limit on rights because they point to the anthropological and ethical framework of which rights are a part, in this way ensuring that they do not become licence. Duties thereby reinforce rights and call for their defence and promotion as a task to be undertaken in the service of the common good. Otherwise, if the only basis of human rights is to be found in the deliberations of an assembly of citizens, those rights can be changed at any time, and so the duty to respect and pursue them fades from the common consciousness.
--Pope Benedict XVI, Caritas in Veritate