Summa Theologica I-II, q. 105: Of the Reason for the Judicial Precepts
But as the town houses were not allotted to distinct estates, therefore the Law allowed them to be sold in perpetuity, like movable goods. Because the number of houses in a town was not fixed, whereas there was a fixed limit to the amount of estates, which could not be exceeded, while the number of houses in a town could be increased. On the other hand, houses situated not in a town, but "in a village that hath no walls," could not be sold in perpetuity: because such houses are built merely with a view to the cultivation and care of possessions; wherefore the Law rightly made the same prescription in regard to both (Lev. 25).
Reply to Objection 4As stated above (ad 1), the purpose of the Law was to accustom men to its precepts, so as to be ready to come to one another's assistance: because this is a very great incentive to friendship. The Law granted these facilities for helping others in the matter not only of gratuitous and absolute donations, but also of mutual transfers: because the latter kind of succor is more frequent and benefits the greater number: and it granted facilities for this purpose in many ways. First of all by prescribing that men should be ready to lend, and that they should not be less inclined to do so as the year of remission drew nigh, as stated in Dt. 15:7, seqq. Secondly, by forbidding them to burden a man to whom they might grant a loan, either by exacting usury, or by accepting necessities of life in security; and by prescribing that when this had been done they should be restored at once. For it is written (Dt. 23:19): "Thou shalt not lend to thy brother money to usury": and (Dt. 24:6): "Thou shalt not take the nether nor the upper millstone to pledge; for he hath pledged his life to thee": and (Ex. 22:26): "If thou take of thy neighbor a garment in pledge, thou shalt give it him again before sunset." Thirdly, by forbidding them to be importunate in exacting payment. Hence it is written (Ex. 22:25): "If thou lend money to any of my people that is poor that dwelleth with thee, thou shalt not be hard upon them as an extortioner." For this reason, too, it is enacted (Dt. 24:10,11): "When thou shalt demand of thy neighbor anything that he oweth thee, thou shalt not go into his house to take away a pledge, but thou shalt stand without, and he shall bring out to thee what he hath": both because a man's house is his surest refuge, wherefore it is offensive to a man to be set upon in his own house; and because the Law does not allow the creditor to take away whatever he likes in security, but rather permits the debtor to give what he needs least. Fourthly, the Law prescribed that debts should cease together after the lapse of seven years. For it was probable that those who could conveniently pay their debts, would do so before the seventh year, and would not defraud the lender without cause. But if they were altogether insolvent, there was the same reason for remitting the debt from love for them, as there was for renewing the loan on account of their need.
As regards animals granted in loan, the Law enacted that if, through the neglect of the person to whom they were lent, they perished or deteriorated in his absence, he was bound to make restitution. But if they perished or deteriorated while he was present and taking proper care of them, he was not bound to make restitution, especially if they were hired for a consideration: because they might have died or deteriorated in the same way if they had remained in possession of the lender, so that if the animal had been saved through being lent, the lender would have gained something by the loan which would no longer have been gratuitous. And especially was this to be observed when animals were hired for a consideration: because then the owner received a certain price for the use of the animals; wherefore he had no right to any profit, by receiving indemnity for the animal, unless the person who had charge of it were negligent. In the case, however, of animals not hired for a consideration, equity demanded that he should receive something by way of restitution at least to the value of the hire of the animal that had perished or deteriorated.
Reply to Objection 5The difference between a loan and a deposit is that a loan is in respect of goods transferred for the use of the person to whom they are transferred, whereas a deposit is for the benefit of the depositor. Hence in certain cases there was a stricter obligation of returning a loan than of restoring goods held in deposit. Because the latter might be lost in two ways. First, unavoidably: i.e. either through a natural cause, for instance if an animal held in deposit were to die or depreciate in value; or through an extrinsic cause, for instance, if it were taken by an enemy, or devoured by a beast (in which case, however, a man was bound to restore to the owner what was left of the animal thus slain): whereas in the other cases mentioned above, he was not bound to make restitution; but only to take an oath in order to clear himself of suspicion. Secondly, the goods deposited might be lost through an avoidable cause, for instance by theft: and then the depositary was bound to restitution on account of his neglect. But, as stated above (ad 4), he who held an animal on loan, was bound to restitution, even if he were absent when it depreciated or died: because he was held responsible for less negligence than a depositary, who was only held responsible in case of theft.
Reply to Objection 6Workmen who offer their labor for hire, are poor men who toil for their daily bread: and therefore the Law commanded wisely that they should be paid at once, lest they should lack food. But they who offer other commodities for hire, are wont to be rich: nor are they in such need of their price in order to gain a livelihood: and consequently the comparison does not hold.
Reply to Objection 7The purpose for which judges are appointed among men, is that they may decide doubtful points in matters of justice. Now a matter may be doubtful in two ways. First, among simple-minded people: and in order to remove doubts of this kind, it was prescribed (Dt. 16:18) that "judges and magistrates" should be appointed in each tribe, "to judge the people with just judgment." Secondly, a matter may be doubtful even among experts: and therefore, in order to remove doubts of this kind, the Law prescribed that all should foregather in some chief place chosen by God, where there would be both the high-priest, who would decide doubtful matters relating to the ceremonies of divine worship; and the chief judge of the people, who would decide matters relating to the judgments of men: just as even now cases are taken from a lower to a higher court either by appeal or by consultation. Hence it is written (Dt. 17:8,9): "If thou perceive that there be among you a hard and doubtful matter in judgment. . . and thou see that the words of the judges within thy gates do vary; arise and go up to the place, which the Lord thy God shall choose; and thou shalt come to the priests of the Levitical race, and to the judge that shall be at that time." But such like doubtful matters did not often occur for judgment: wherefore the people were not burdened on this account.
Reply to Objection 8In the business affairs of men, there is no such thing as demonstrative and infallible proof, and we must be content with a certain conjectural probability, such as that which an orator employs to persuade. Consequently, although it is quite possible for two or three witnesses to agree to a falsehood, yet it is neither easy nor probable that they succeed in so doing: wherefore their testimony is taken as being true, especially if they do not waver in giving it, or are not otherwise suspect. Moreover, in order that witnesses might not easily depart from the truth, the Law commanded that they should be most carefully examined, and that those who were found untruthful should be severely punished, as stated in Dt. 19:16, seqq.
There was, however, a reason for fixing on this particular number, in token of the unerring truth of the Divine Persons, Who are sometimes mentioned as two, because the Holy Ghost is the bond of the other two Persons; and sometimes as three: as Augustine observes on Jn. 8:17: "In your law it is written that the testimony of two men is true."
Reply to Objection 9A severe punishment is inflicted not only on account of the gravity of a fault, but also for other reasons. First, on account of the greatness of the sin, because a greater sin, other things being equal, deserves a greater punishment. Secondly, on account of a habitual sin, since men are not easily cured of habitual sin except by severe punishments. Thirdly, on account of a great desire for or a great pleasure in the sin: for men are not easily deterred from such sins unless they be severely punished. Fourthly, on account of the facility of committing a sin and of concealing it: for such like sins, when discovered, should be more severely punished in order to deter others from committing them.