Justice is a true relation existing between two things; a relation which is always the same, whoever contemplates it, whether it be God, or an angel, or lastly, man himself.
It is true that men do not always perceive these relations: often indeed, when they do perceive them, they turn aside from them, their own interest being always that which they perceive most clearly. Justice cries aloud
 Montesquieu, Persian Letters (1721). copy citation

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Author Montesquieu
Source Persian Letters
Topic justice interest
Date 1721
Language English
Reference
Note Translated by John Davidson
Weblink https://en.wikisource.org/wiki/Persian_Letters

Context

“Paris, the 6th of the second moon of Rebiab, 1715. Letter 84 Usbek to Rhedi, at Venice IF there is a God, my dear Rhedi, HE must of necessity be just; because, if He were not so, He would be the worst and most imperfect of all beings. Justice is a true relation existing between two things; a relation which is always the same, whoever contemplates it, whether it be God, or an angel, or lastly, man himself. It is true that men do not always perceive these relations: often indeed, when they do perceive them, they turn aside from them, their own interest being always that which they perceive most clearly. Justice cries aloud; but her voice is hardly heard in the tumult of the passions. Men act unjustly, because it is their interest to do so, and because they prefer their own satisfaction to that of others. They act always to secure some advantage to themselves:” source