Adam Smith. An inquiry into the nature and causes of the wealth of Nations (№ 347144)

A coward man, unable to protect themselves or to avenge himself obviously lacks one of the main features of human character. His spirit is crippled and disfigured as the human body, deprived of any important member or have lost the ability to wield it. Of these two people first, obviously, the more unhappy and miserable, because happiness and unhappiness, which is merely a state of mind, must depend more on healthy or unhealthy, the mutilated or normal state of mind than state of body...
The same can be said of the gross ignorance and stupidity which in a civilized society so often freezes the mind of all the lower classes of the people. A man devoid of mental faculties, is even more pathetic than a coward, and seems mutilated and disfigured in the more important qualities of human nature.