There are limits to the smiles and scowls of diplomacy. Armies and missiles are not stopped by stiff notes of condemnation. They are held in check by strength and purpose and the promise of swift punishment.
Exemplary people concern themselves with virtue,
small people concern themselves with territory. The ruling class
thinks of punishment, the lower classes hope for benevolence.
Capital punishment kills immediately, whereas lifetime imprisonment does so slowly. Which executioner is more humane? The one who kills you in a few minutes, or the one who wrests your life from you in the course of many years?
Even if a civil society were to be dissolved by the consent of all its members (e.g., if a people inhabiting an island decided to separate and disperse throughout the world), the last murderer remaining in prison would first have to be executed, so that each has done to him what his deeds deserve and blood guilt does not cling to the people for not having insisted upon this punishment; for otherwise the people can be regarded as collaborators in his public violation of justice.
If the people be led by laws, and uniformity sought to be given them by punishments, they will try to avoid the punishment, but have no sense of shame.
My position concerning God is that of an agnostic. I am convinced that a vivid consciousness of the primary importance of moral principles for the betterment and ennoblement of life does not need the idea of a law-giver, especially a law-giver who works on the basis of reward and punishment.
It isn't the desire to abide by the law that makes everyone behave as society requires, but the fear of punishment. Each one of us carries a gallows inside us.