Answer. That I promote the advantage of my neighbor in every instance I can or may, and deal with him as I desire to be dealt with by others; further ALSO, that I faithfully labor, so that I may be able to relieve the needy.
Exposition
This commandment sanctions and authorises a distinction in property or possessions. The end or design of this commandment is, the preservation of the property or possessions which God has given to every one for the support of life: for if it is not lawful or becoming for us to steal, it is necessary that every man should possess that which lawfully belongs to him. God, therefore, in this commandment, forbids all frauds, together with all the cunning devices and arts by which the goods and possessions of our neighbor are injured, diminished or confounded so as to lose his right in them, or to make it doubtful. In forbidding these things, God at the same time enjoins all those virtues which contribute to the preservation of our neigbor’s goods and possessions. Thou shalt not steal, that is, thou shalt not desire, or attempt to take to thyself thy neighbor’s goods by fraud. Therefore, thou shalt defend, preserve and increase them, and give unto thy neighbor what belongs to him. God calls the things that are forbiddeit theft, in order that he might comprehend and condemn under this, as being the grossest kind of fraud, all other sins of a kindred nature, with their antecedents and consequents.
The virtues of the eighth commandment
I. COMMUTATIVE JUSTICE is a virtue in the acquisition of goods, which does not desire the possessions of another, and contributes to an arithmetical equality in contracts and in the ordinary traffic amongst men in the purchase and exchange of goods according to just laws. Commutative justice then consists in preserving an equality between merit and reward, wages and labor, &c., whether it be in the acquisition, or disposition of goods. Justinian, the Roman emperor, writes in relation to the possession and division of things: that some things are common to all by natural right, as the air, water, the sea, the shores of the sea, &c. Some things are public, as rivers, ports, the use of the banks of rivers, &c. Some belong to no one as things sacred, religious, and holy. The largest amount of things, however, belong to persons privately and singly, and are acquired in various ways. Those things, therefore, which are transferred to another owner, or which any one takes to himself, belong either to no one, or to some one. Those which belong to no one, become the property of the persons who acquire them. Those things which belong rightly to some one, can only pass into the hands of others, either by violence and against the will of the rightful owner, or by captivity in war; or with the consent of the owner, as by inheritance, or contract. Possessions pass into the hands of others by inheritance, either by will, or without any will. A contract is an agreement between certain persons in reference to the transfer, giving, or exchange of possessions according to just and wholesome laws. All contracts are included under commutative justice, and may be comprehended under ten classes. 1. Buying and selling, when an article passes from the vender to the purchaser, in such a way that the purchaser gives a just and equivalent price for it. This is sometimes accompanied with a condition of selling it again, or it may be without this condition. The buying of revenues, or the receiving an income belongs to this, and is no more to be regarded as usury, than the letting out of land, for which a certain yearly rent is required. 2. Borrowing is a contract according to which the use of a certain thing is transferred to another, in such a way that he returns that which is equivalent. There is something given in borrowing, not that the same thing may be returned, but only that which is similar or of equal value. Lending is that which takes place when the use of a certain thing is granted to some one for a certain length of time, when he is to return the self-same thing whole and without any injury, without having to pay any remuneration for the use of it. 4. Donation, when a certain thing is transferred to another person, without recompense, by the rightful owner, who alone has the right to give it by free will. But, should some one say, that justice demands that like should be given for like; and that inasmuch as this is not done in what is given as a donation, it must conflict with justice; we would reply that this is true only in case the things are given with the intention that a compensation be made. 5. Exchange, when things are exchanged by the consent of those who are the lawful owners, or when one thing is given for another which is equal in value. 6. Leasing or letting out, is a contract according to which the use of a certain thing, without any right of possession, is given over to another person by the rightful owner, for a certain length of time, upon the condition that he to whom it is leased pay a given sum for its use, and return it again in a proper state at the expiration of the time for which it was let. 7. Pledging or mortgaging is when a certain thing is transferred to another person, which gives him a right to it as long as certain things which are due him are not paid; or it is a contract which takes place when a certain thing is delivered to another person upon this condition, that he has the right of using it according to his own pleasure, in case it is not redeemed within a given time. 8. Committing in trust, is a contract according to which neither the use nor possession, but only the keeping of a certain thing is entrusted to another person. 9. Partnership is a contract between certain persons, who associate themselves together in business, according to which one person gives his funds, and the other his attention or labor, upon the condition that they receive or bear an equal proportion of the loss or gain, and that neither one reap the entire gain, or sustain the whole loss. 10. There is, lastly, a contract according to which the use or possession of a piece of land is transferred by the owner to a farmer to till, upon the condition that he cultivate it, and be bound to render to the owner thereof some particular service. These different kinds of contracts are to be observed for the better understanding of commutative justice.