The Theory of Moral Sentiments by Adam Smith

All those systems, which I have hitherto given an account of, suppose that that there is a real and essential distinction between vice and virtue, whatever these qualities may consist in. There is a real and essential difference between the propriety and impropriety of any affection, between benevolence and any other principle of action, between real prudence and shortsighted folly or precipitate rashness. In the main, too, all of them contribute to encourage the praiseworthy, and to discourage the blameable disposition.

It may be true, perhaps, of some of them, that they tend, in some measure, to break the balance of the affections, and to give the mind a particular bias to some principles of action, beyond the proportion that is due to them. The ancient systems, which place virtue in propriety, seem chiefly to recommend the great, the awful, and the respectable virtues, the virtues of self-government and self-command; fortitude, magnanimity, independency upon fortune, the contempt of all outward accidents, of pain, poverty, exile and death. It is in these great exertions that the noblest propriety of conduct is displayed. The soft, the amiable, the gentle virtues, all the virtues of indulgent humanity are, in comparison, but little insisted upon, and seem, on the contrary, by the Stoics in particular, to have been often regarded as weaknesses, which it behoved a wise man not to harbour in his breast.