Such is the account commonly given of our approbation of the punishment of injustice. And so far this account is undoubtedly true, that we frequently have occasion to confirm our natural sense of the propriety and fitness of punishment, by reflecting how necessary it is for preserving the order of society. When the guilty is about to suffer that just retaliation, which the natural indignation of mankind tells them is due to his crimes; when the insolence of his injustice is broken and humbled by the terror of his approaching punishment; when he ceases to be an object of fear, with the generous and humane he begins to be an object of pity. The thought of what he is about to suffer extinguishes their resentment for the sufferings of others to which he has given occasion. They are disposed to pardon and forgive him, and to save him from that punishment, which in all their cool hours they had considered as the retribution due to such crimes. Here, therefore, they have occasion to call to their assistance the consideration of the general interest of society. They counterbalance the impulse of this weak and partial humanity by the dictates of a humanity that is more generous and comprehensive. They reflect that mercy to the guilty is cruelty to the innocent, and oppose to the emotions of compassion which they feel for a particular person, a more enlarged compassion which they feel for mankind. 
 --Adam Smith (The Theory of Moral Sentiments, 1759)