former method can be clearly shown to be the more desirable....  It is more admirable that a State should possess an abundance of riches from its own soil than through commerce.  For the State which needs a number of merchants to maintain its subsistence is liable to be injured in war through a shortage of food if communications are in any way impeded.  Moreover, the influx of strangers corrupts the morals of many of the citizens... whereas, if the citizens themselves devote themselves to commerce, a door is opened to many vices.  For when the desire of merchants is inclined greatly to gain, cupidity is aroused in the hearts of many citizens....  For the pursuit of a merchant is as contrary as possible to military exertion.  For merchants abstain from labours, and while they enjoy the good things of life, they become soft in mind and their bodies are rendered weak and unsuitable for military exercises....  It therefore behoves the perfect State to make a moderate use of commerce.’[1]

[Footnote 1:  ii. 3.]

Aquinas, who, as we have seen, recognised the necessity of commerce, did not condemn all trade indiscriminately, as the Fathers had done, but made the motive with which commerce was carried on the test of its legitimacy:  ’Trade is justly deserving of blame, because, considered in itself, it satisfies the greed for gain, which knows no limit, and tends to infinity.  Hence trading, considered in itself, has a certain debasement attaching thereto, in so far as, by its very nature, it does not imply a virtuous or necessary end.  Nevertheless gain, which is the end of trading, though not implying, by its nature, anything virtuous or necessary, does not, in itself, connote anything sinful or contrary to virtue; wherefore nothing prevents gain from being directed to some necessary or even virtuous end, and thus trading becomes lawful.  Thus, for instance, a man may intend the moderate gain which he seeks to acquire by trading for the upkeep of his household, or for the assistance of the needy; or again, a man may take to trade for some public advantage—­for instance, lest his country lack the necessaries of life—­and seek gain, not as an end, but as payment for his labour.’[1] This is important in connection with what we have said above as to property, as it shows that the trader was quite justified in seeking to obtain more profits, provided that they accrued for the benefit of the community.  This justification of trade according to the end for which it was carried on, was not laid down for the first time by Aquinas, but may be found stated in an English treatise of the tenth century entitled The Colloquy of Archbishop Alfric, where, when a doctor asks a merchant if he wishes to sell his goods for the same price for which he has bought them, the merchant replies:  ’I do not wish to do so, because if I do so, how would I be recompensed for my trouble? but I wish to sell them for more than I paid for them so that I might secure some gain wherewith to support myself, my wife, and family.’[2]