Humanly speaking, in default of natural sanctions, the laws of justice are ineffective among men: they merely make for the good of the wicked and the undoing of the just, when the just man observes them towards everybody and nobody observes them towards him.
 Jean-Jacques Rousseau, The Social Contract (1762). copy citation

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Author Jean-Jacques Rousseau
Source The Social Contract
Topic justice law
Date 1762
Language English
Reference Of the Social Contract, or Principles of Political Law, Book II
Note Translated by George Douglas Howard Cole
Weblink https://en.wikisource.org/wiki/The_Social_Contract/Book_II

Context

“but if we knew how to receive so high an inspiration, we should need neither government nor laws. Doubtless, there is a universal justice emanating from reason alone; but this justice, to be admitted among us, must be mutual. Humanly speaking, in default of natural sanctions, the laws of justice are ineffective among men: they merely make for the good of the wicked and the undoing of the just, when the just man observes them towards everybody and nobody observes them towards him. Conventions and laws are therefore needed to join rights to duties and refer justice to its object. In the state of nature, where everything is common, I owe nothing to him whom I have promised nothing;” source