Politeness is so much the virtue of the great, that it will do little honour to any body but themselves.
 Adam Smith, The Theory of Moral Sentiments (1759). copy citation

Context

“Knowledge, industry, valour, and beneficence, trembled, were abashed, and lost all dignity before them. But it is not by accomplishments of this kind, that the man of inferior rank must hope to distinguish himself. Politeness is so much the virtue of the great, that it will do little honour to any body but themselves. The coxcomb,12 who imitates their manner, and affects to be eminent by the superior propriety of his ordinary behaviour, is rewarded with a double share of contempt for his folly and presumption. Why should the man, whom nobody thinks it worth while to look at, be very anxious about the manner in which he holds up his head, or disposes of his arms while he walks through a room?” source