Righteousness and unrighteousness must be taken together; it is impossible to stress the one without stressing the other also. Now, what is "unrighteousness" in practise? It is in practise behaviour of a kind disliked by the herd. By calling it unrighteousness, and by arranging an elaborate system of ethics around this conception, the herd justifies itself in wreaking punishment upon the objects of its own dislike, while at the same time, since the herd is righteous by definition, it enhances its own self-esteem at the very moment when it lets loose its impulse to cruelty. This is the psychology of lynching, and of the other ways in which criminals are punished. The essence of the conception of righteousness, therefore, is to afford an outlet for sadism by cloaking cruelty as justice.
Source: Bertrand Russell: Has Religion Made Useful Contributions to Civilization? 1930.
More info.:http://russell-j.com/beginner/0466HRMUC-170.HTM