11. Likewise homicide is committed interpretively, and this occurs in three ways: first, by omitting in deed: whence Ambrose says: "Feed the one dying of hunger: if you have not fed him, you have killed him." — In the second way it occurs when someone kills another by counseling, or accusing, or disparaging, when he does this from malice of spirit. — In the third way homicide is committed interpretively by hating in the soul: whence in the epistle of John: He who hates his brother is a murderer.
I say therefore that according to the principal meaning, what is prohibited here is killing — not that which is by law, but that which is by man — and that which is done willfully or interpretively: and this is what it says: You shall not kill.
The Sixth Commandment.
12. There follows: You shall not commit adultery. Here it is commanded that no one violate the wife of his neighbor. And blessed Augustine says that here is prohibited every illicit use of the generative members, which is done for the pursuit of lust with an assault upon chastity. And this occurs in seven ways, namely through adultery, fornication, prostitution, defilement, sacrilege, incest, and the sin against nature.
13. It should be noted that there is conjugal, common, and privileged modesty. Accordingly I say that one can be an assailant of conjugal modesty, and this is called adultery: or one is an assailant of common chastity, and this is done either with an unattached woman simply, and is called fornication, or with an unattached woman who is vagrant and prostituted, and is called prostitution. If however someone is an assailant of privileged modesty, that is, of virginity, this is twofold: either it is done with an attached condition, which is deflowering, and thus it is called defilement: or it is done with a woman consecrated to God, and thus it is called sacrilege, namely when someone violates a woman consecrated to the Lord.
But if it is done against the foundation of all these, then it is called sin against nature: and this is done in two ways: either against the dictate of natural reason, namely against that "which nature has taught all animals," and thus it is properly called sin against nature: or it is done against the instinct of nature, and in this way it is incest, namely when someone sins with a person related to him. - Sin against nature is the most wicked and is to be fled above all others. And concerning this crime, Joseph accused his brothers before their father of a most grievous crime.
14. He says therefore: You shall not commit adultery. It is clear, first, how here all adultery with a neighbor's wife is prohibited; and according to Augustine, all illicit use of the generative members is prohibited, which is done for the procurement of lust with an assault upon chastity. It is also clear on what basis the seven transgressions of this commandment are understood: You shall not commit adultery: and that sin against nature is to be fled above all others.
15. Peter Damian relates that two men were together in the desert who performed the harshest penance. One of them was unlearned and, on account of his sins, was deceived by the devil, who told him that the sin of pollution against nature was no greater a sin than blowing mucus from one's nose. And then that wretched man practiced that shameful act. At death the devil carried away his soul. Seeing this, the other was amazed that a man of such great vigils and sufferings should be lost. And then an Angel of the Lord appeared, who related to him that he had defiled everything through such a sin.
16. Every act, therefore, that consists in the experience of lust, in whatever way a man may devise the sin itself, is prohibited, unless it is done in the form of marriage of the Church.
In sleep a man sometimes suffers pollutions without fault and without cause. A certain foolish priest said to one confessing to him about nocturnal pollution: can you not give a coin to fulfill your lust?
It is now clear how all illicit use of the body and of lust, procured outside the form of marriage, is here prohibited.
The Seventh Commandment.
17. There follows: You shall not steal. Theft is the handling of another's property, against the owner's will, out of greed.
If it is done not out of greed, as the children of Israel by the Lord's command carried with them from Egypt vessels of silver and gold, or when someone takes a sword from another lest he do harm, then he is not said to commit theft.
18. Theft, moreover, is divided into parts, because theft is the handling of another's property, against the owner's will: and this is done either through mere fraud, or through violence, or through circumvention.
If it is done through mere fraud and furtively, then it is called theft.
If it is done through violence, either that violence is open, and thus it is called robbery: or it is hidden, and thus it is called brigandage.
If indeed the handling of another's property occurs through circumvention, this can happen with an attached agreement, and this in three ways: either with a fraudulent agreement, or an unjust one, or a profane one. The first way occurs in business transactions, and this happens in three ways, namely either in weight, or in number, or in measure: and from this merchants very rarely escape. If however it is done with an unjust agreement, thus it is usury, in which that which is sold is common, namely time. If however it is done with a profane agreement, in which what is proper to God is sold, thus it is simony.
19. But it is asked: why, if I lend you a garment or a horse or a house for money, is it not usury, as it is with money?
I say that in a garment or a horse or a house, the use is drawn from the thing, not from money: and therefore it is not called usury. Some believe that usury is evil because it is prohibited: but certainly it is prohibited because it is evil. In a loan, what is mine becomes yours; and if you acquire something through your own industry from that loan, and I demand something back from it, I sell time, which is common, and which it is not lawful to sell. But in a loan for use, my property does not pass into yours, as in a loan my money becomes yours; and the money is not diminished nor deteriorated, as happens with a house or a garment or a horse, because one must return the money whole and entire. And therefore, when through usury a man seeks something, there is a perversion of order and an appropriation of what is common: and everyone ought to guard himself against this. Thus therefore, when circumvention occurs with an unjust agreement, it is called usury.
20. If however circumvention occurs with a profane agreement, it is called simony , in which he who buys acquires nothing, nor does he who sells possess anything, but they only handle another's property: and this happens when a spiritual thing is sold as though it were a cheap thing. Against whom the Lord says: Do not make my Father's house a house of trade. But some make it a den of thieves; whence: Her princes judged for bribes, and her priests taught for hire, and her prophets divined for money. Let us therefore beseech the Lord Jesus Christ, etc.