Father Pegues continues his discussion of sins against commutative justice by elaborating upon fraud and usury, which are “sins whereby our neighbour is induced to agree to things that are prejudicial to him.”
Fraud is committed “in buying and selling whereby our neighbour is deceived and is led to will what is to his loss.” There are four ways fraud might be committed.
Fraud might be committed when the price is more than a thing is worth. Father Pegues states that “the price of a thing bought or sold must always correspond to the worth of the thing itself; to ask more or to give less knowingly is of itself essentially unjust, and obliges to restitution.”
A second way fraud might be committed is when the thing sold is not what it appears to be, the seller knowing this, and the buyer being unaware of it. “To sell or to buy a thing which is other than it appears to be, whether there be question of its substance, or its quantity or quality, is contrary to justice, and is a sin if one do this knowingly; moreover, one is bound to make restitution. Further, this obligation of making restitution exists even when there has been no sin, as soon as ever one discovers the disproportion between the price and the thing sold or bought.”
A third way fraud might be committed is when the seller conceals a defect in the object sold. The seller is bound to bring to the notice of the buyer any hidden defects of his merchandise, insofar as he knows them, that “might be a cause of danger or loss to the buyer.”
A fourth way fraud might be committed is when a person engages in “buying and selling as a form of trade for the sake of gaining money,” that is, “trading for the sake of trading.” Father Pegues asserts that this is “a shameful thing and contrary to justice; because of itself it promotes the love of lucre, which knows no limits, but seeks to acquire without end.” He explains that money “should not be sought after for its own sake but for some good end. In this way one may seek a moderate gain by trading in order to maintain one’s household, or to give help to the needy, or one may do this for the public benefit to the end that one’s fellow-men may not lack the things necessary for daily life, and one may seek such gain not as an end in itself but as the recompense for one’s work.”
Usury is an act of injustice because it takes advantage of a person in need. But not all lending at interest is usury. “In order that lending at interest may be allowable and may not run the risk of becoming usury two things are necessary: first, the amount of interest charged must not exceed the legal charge, or the charge fixed by reasonable custom; and second, those who are well off should not be exacting towards the poor who have need of borrowing.”
Quotations from Thomas Pegues, Catechism of the “Summa Theologica” of Saint Thomas Aquinas, trans. Aelred Whitacre (New York: Benziger, 1922).