Goods can serve many other purposes besides purchasing money, but money can serve no other purpose besides purchasing goods. - Adam Smith

We do not, however, reckon that trade disadvantageous which consists in the exchange of the hard-ware of England for the wines of France;and yet hard-ware is a very durable commodity, and were it not for this continual exportation, might too be accumulated for ages together, to the incredible augmentation of the pots and pans of the country. But it readily occurs that the number of such utensils is in every country necessarily limited by the use which there is for them;that it would be absurd to have more pots and pans than were necessary for cooking the victuals usually consumed there;and that if the quantity of victuals were to increase, the number of pots and pans would readily increase along with it, apart of the increased quantity of victuals being employed in purchasing them, or in maintaining an additional number of workman whose business it was to make them.

Labour was the first price, the original purchase-money that was paid for all things. It was not by gold or by silver, but by labour, that all the wealth of the world was originally purchased; and its value, to those who possess it, and who want to exchange it for some new productions, is precisely equal to the quantity of labour which it can enable them to purchase or command.

No regulation of commerce can increase the quantity of industry in any society beyond what its capital can maintain. It can only divert a part of it into a direction into which it might not otherwise have gone; and it is by no means certain that this artificial direction is likely to be more advantageous to the society than that into which it would have gone of its own accord. Every individual is continually exerting himself to find out the most advantageous employment for whatever capital he can command. It is his own advantage, indeed, and not that of the society, which he has in his view. But the study of his own advantage naturally, or rather necessarily leads him to prefer that employment which is most advantageous to the society.