"But what all the violence of the feudal institutions could never have effected, the silent and insensible operation of foreign commerce and manufactures gradually brought about. These gradually furnished the great proprietors with something for which they could exchange the whole surplus produce of their lands, and which they could consume themselves without sharing it either with tenants or retainers. All for ourselves and nothing for other people, seems, in every age of the world, to have been the vile maxim of the masters of mankind. As soon, therefore, as they could find a method of consuming the whole value of the rents themselves, they had no disposition to share them with any other persons. For a pair of diamond buckles, perhaps, or for something as frivolous and useless, they exchanged the maintenance, or what is the same thing, the price of the maintenance of a thousand men a year, and with it the whole weight and authority which it could give them. The buckles, however, were to be all their own, and no other human creature was to have any share of them; whereas in the more ancient method of expense the must have shared with at least a thousand people. With the judges that were to determine the preference this difference was perfectly decisive; and thus, for the gratification of the most childish, the meanest, and the most sordid of all vanities, they gradually bartered their whole power and authority." Wealth of Nations III.iv.10
It is very often misquoted and I know Noam Chomsky has referred to that line countless times along with many others.