The Theory of Moral Sentiments by Adam Smith

Upon these two different efforts, upon that of the spectator to enter into the sentiments of the person principally concerned, and upon that of the person principally concerned to bring down his emotions to what the spectator can go along with, are founded two different sets of virtues. The soft, the gentle, the amiable virtues, the virtues of candid condescension and indulgent humanity, are founded upon the one: the great, the awful and respectable, the virtues of self-denial, of self-government, of that command of the passions which subjects all the movements of our nature to what our own dignity and honour, and the propriety of our own conduct require, take their origin from the other.

How amiable does he appear to be, whose sympathetic heart seems to reecho all the sentiments of those with whom he converses, who grieves for their calamities, who resents their injuries, and who rejoices at their good fortune! When we bring home to ourselves the situation of his companions, we enter into their gratitude, and feel what consolation they must derive from the tender sympathy of so affectionate a friend. And for a contrary reason, how disagreeable does he appear to be, whose hard and obdurate heart feels for himself only, but is altogether insensible to the happiness or misery of others! We enter, in this case, too, into the pain which his presence must give to every mortal with whom he converses, to those especially with whom we are most apt to sympathize, the unfortunate and the injured.