Part VI: The Sixth Commandment.
PART VI: THE SIXTH COMMANDMENT OF THE DECALOGUE
§ 159. The Sixth Commandment is: “You shall not commit adultery” [Exod. 20:14]. (1) The word 
properly means “to commit adultery,” from “agitate” or “fornicate with.” Here it is used by synecdoche for every species of illicit lust, as the prophets’ and apostles’ interpretation of this commandment shows. That is why in Matt. 15:[19] Christ connects adultery and fornication [μoιχείαν καὶ πoρνείαν].
** Some think that 
means to fornicate [scortari]58 (Job 24:15; Jer. 3:9). However, examples from Scripture show that 
properly means “to commit adultery” (Lev. 20:10; Prov. [6]:32; Hosea 4:13). In Job the situation refers not to a fornicator [scortator] but properly to an adulterer because fornicators do not seek the darkness as much as do adulterers. In Jer. 3:9 the two words are connected—
and 
—not as synonyms or equivalents, but rather the first, being the more general, is declared by the second as the more particular. **
(2) Not only the outward sins of fornication, adultery, etc., but also the inner fires of lust are forbidden by this commandment. Matt. 5:28: “Everyone who looks at a woman lustfully has already committed adultery with her in his heart.”
(3) Moreover, all those things that increase or arouse illicit fires of lusts are forbidden. Where the effect is condemned, there the cause is also understood to be condemned. Ezek. 16:49: “Behold, this was the guilt of your sister Sodom: she and her daughters had pride, surfeit of bread, and abundance of ease.”
(4) Inner and exterior sins against chastity are expressed by the word for the crasser sin to make clear what place they have before God’s judgment, lest we be deluded about the corruption of our heart.
(5) Because God heartily detests all impurity, He expressly forbids violating the marriage bed that we may understand that the divinely sanctioned order of marriage is confirmed and its dignity is defended by His Law.
(6) Without any specification or limitation adultery is forbidden to all so that no one can use his person or station as an excuse.
(7) The sound of the prohibitive law accuses the extreme corruption of our nature by which we are prone and inclined to lusts of every kind.
(8) The affirmative should be deduced from what is stated in the negative so that it may be clear that the end purpose and aim of this commandment is the preservation of chastity and the strengthening of marriage.
The virtues required in the Sixth Commandment.
§ 160. On this basis one can easily determine what virtues are required in this commandment. The principal and primary virtue of this commandment is chastity [castitas], which some try to derive from κάζω (that is, “I adorn”), because chastity is man’s greatest adornment since it is the virtue by which the cleanness of mind and body is preserved, coming from true fear and love of God, and by which all the lusts that God has forbidden are avoided. In 1 Thess. 4:4 it is called by the very beautiful noun ἁγιασμός [“holiness”]; in Gal. 5:23, ἐγκράτεια [“self-control”]; in Ps. 51:[10], “cleanness”; etc.
There are two kinds of chastity with respect to different subjects: chastity of celibate life and chastity of married life. The former is not only to keep the body uncorrupted but also to have a mind free of the fires of lust. That is how the apostle defines it (1 Cor. 7:34): “that she may be holy in both body and spirit.” However, the latter is to keep one’s body holy and chaste for one lawfully wedded spouse and reverently to regard the divinely sanctioned laws of marriage. This virtue should have its base in the heart, it should shine forth in one’s attitudes and speech, and it should finally appear in his deeds.
(1) In one’s heart there should be a serious eagerness for chastity; one should acknowledge that God has a chaste mind and strictly demands chastity from us. The flames of lust must be absent, and there should be no corrupt desires.
(2) Decency and modesty [pudor ac verecundia] should rule in our words and attitudes to testify that we abhor every shameful act. We should beware of filthy talk, indecent gestures, leering eyes, etc.
(3) Chastity should be shown in our deeds so that the body may be kept pure and unsullied. We should be on guard against the misuse of semen and against all illicit intercourse and defilement of bodies. This virtue is served by moderation, which in food, drink, sleep, leisure, etc., follows the order of nature that accords with honorable and right reason, lest the passions of desire and the flames of lusts be kindled. Furthermore, the married estate is divinely sanctioned here because true and God-pleasing chastity exists in marriage. Thus to this commandment belong the laws of marriage as sanctioned in Genesis 2 and often repeated afterward to establish the duties of husbands and wives. We shall speak about these in greater detail in its own place [On Marriage, Celibacy, and Similar Topics (Commonplace XXVIII)].
The sins against the Sixth Commandment.
§ 161. The antithesis shows which sins conflict with this commandment. (1) Corrupt desires in the heart, the fires of lusts, which the apostle calls “burning” (1 Cor. 7:9). Matt. 15:19: “For out of the heart come fornication, adultery, evil thoughts.”
(2) In words: smut, shameful talk, obscenity. In gestures: any signs of wantonness, lust of the eyes. Ecclesiasticus 26:9: “A woman’s fornication is recognized by her eyes and eyelids.” Also, immodest embraces and kisses. Jer. 5:8: “Each was neighing after his neighbor’s wife.”
(3) In action, people sin in various ways against this commandment: through fornication, among unwed persons; through adultery, among married persons; through rape, when violation is brought on a woman by force; through incest, when there is a union of blood kin and relatives in prohibited grades; through sodomy, bestiality, pederasty, softness ([mollities], that is, the voluntary emission of semen, which Thomas declares “is a sin worse even than fornication”); through concubinage with prostitutes.
Since to avoid sins is to avoid opportunities to sin, sins against this commandment also include: intemperance, drunkenness, extravagance, dressing provocatively [levitas vestium], immodest dancing, laziness and negligence, impure reading, love songs [amatoriis cantilenis],59 building and tolerating whorehouses.
Finally, because marriage is sanctioned in this commandment, it is sin against this commandment to denigrate marriage and the female sex, to divorce rashly, to pretend chastity outside of marriage, to prohibit marriage between suitable persons, and to neglect the duties which Scripture commands to spouses.
All this should be illustrated by statements from Holy Writ. Promises and warnings should be added, as well as examples of rewards and punishments. Compelling reasons should be listed, which ought to encourage us to chastity, and it should be shown how savagely detestable is the sin of adultery and fornication. However, to spend time doing this is not our purpose.
What adultery is, properly speaking.
§ 162. The question arises: (I) What is adultery, properly speaking?
We respond. Rabbi Salomon says, “There is no adultery unless it is with a man’s wife.” That is, adultery can be committed only with a married woman, not a single woman. Lyra follows him when he defines adultery as “fleshly union with another man’s wife, for she is considered to be one flesh with him.” However, those are more correct who teach that adultery is committed by any violation of the marriage bed or promise. Whether such union happens with an unmarried or a married woman, it is a heinous union. This is the law of marriage (1 Cor. 7:4): “A man does not have authority over his own body, nor does a woman.” Therefore it is adultery if either spouse entrusts authority over his body to others. The corruption of marital unity is called “adultery” [adulterium] because that which was unstained is defiled [adulteratur] and corrupted by the admission of another body, even if one does not go to another’s bed. In Prov. 7:5[–23] the woman who gives the power over her body to a young man is accused of adultery.
There are really two kinds of adultery: simple, when one’s own marriage bed is violated, as, for instance, when a married man has an affair with an unmarried woman or when an unmarried man defiles another’s wife; and double, when not only one’s own marriage bed but also that of another is violated, as, for instance, when a married man violates someone else’s bed or when a married woman gives power over her body to another married man.
Whether brothels should be tolerated.
§ 163. (II) The question arises: Is the toleration of brothels a sin against the Sixth Commandment? We respond.
** Luther (commentary on Genesis 19, f. 229) denies this in a few words.60 Paul III at one time indicated that he was planning to cleanse the church, and he gave that task to some cardinals and bishops who were considered purer than others. What they thought is found in Conciliorum (vol. 3): “They complain that the influence of prostitutes in Rome is greater than anywhere else.” Did Paul III clean this up? Also, in the Council of Trent the Romanists promised a sort of great housecleaning, but they neither accomplished it nor did they even try. Why do they not imitate and follow the laws of Justinian instead? He wants ([Corpus Iuris Civilis,] Authent., tit. De lenonibus) “prostitutes to be eliminated completely from the cities. They should not be obligated nor bound if they have made promises to their pimps. In fact, if they swore that they would be prostitutes for any period of time, he freed them from their oath.” **
However, the Roman leader61 not only tolerates houses of prostitution but even receives an annual tax from prostitutes, which was discovered to exceed several thousands of florins every year. Stanislaus Orichonius (De lege caelibat.) and Hieronymus Marius (Eusebius captivus) report that in his forty-second year Paul III had on his lists forty-five thousand prostitutes, from whose fornication he demanded an accounting every month, and each contributed according to how beautiful she was. And yet he rightly brandishes all those detestations of prostitution which occur in the prophetic and apostolic writings against public houses of prostitution, which are the schools of all impurity and uncleanness. Deut. 23:17: “Let there be no whore or prostitute in Israel.” Augustine said (De ordine): “Take away the prostitutes, and everthing will be filled with lusts.” This should not be used as an excuse, since we should not “do evil that good may come” (Rom. 3:8). Augustine wrote this while still a catechumen and not yet sufficiently instructed in [true] religion. It is more accurate to say the reverse: “Support prostitutes, and you will fill everything with lusts.” Basil says (commentary on Psalm 1):
Fornication does not stop with one man but pervades the entire state. One young man goes to a prostitute, then draws to himself a comrade, and he likewise another. So just as a fire started in a city does not stay burning in one or two houses when the wind blows harder but spreads far and wide and brings great destruction with it, so also this wickedness, once it has been kindled, spreads through all the parts of the city.
To be sure, civil laws do not refuse to prescribe some things regarding the price or wage given or promised to a prostitute ([Corpus Iuris Civilis,] l., Idem etsi, ff. De condict. ob turpem causam; l. Affectionis, ff. De donationibus). On this basis some conclude that prostitutes are not removed from the Roman dominion by civil laws. However, we respond from Jerome (Epitaph. Fabiolae), where he speaks about this subject and says: “We should not be so eager to cite civil laws. Papinianus writes one thing; Paul, another.” The divine ordinance of the Law is clear (Deut. 23:18): “You shall not bring the fee of a prostitute into the house of Jehovah your God, because it is an abomination to Jehovah.”
The nature and magnitude of the sin of adultery.
§ 164. (III) The question arises: Should adultery be considered as an enormous and detestable crime?
We respond. Alexander III ([Ius canonicum], Extra, De judiciis, c. At si clerici) gave a rescript to the archbishop of Salers: “In regard to adultery and other crimes that are lesser, the bishop can give dispensation to a clergyman after his penance is completed.” From this it is apparent that the Roman pope considers adultery to be among the lesser sins. The codex of divine Law speaks otherwise and not only orders an adulterer to be punished with death (Lev. 20:10; Deut. 22:22) but also excludes him from the kingdom of God (1 Cor. 6:13; Gal. 5:21). This sin is contrary to the laws of the marriage covenant which was initiated in the presence of God and the church. Therefore surely the adulterer must be regarded as a covenant-breaker. Thus Christ declares that a marriage can be dissolved because of adultery (Matt. 5:32). Chrysostom (on John, homily 62) went so far as to say that “adultery is a sin more serious than idolatry.” Although it would not seem right to affirm this simply and absolutely, there is a strong connection between idolatry and adultery, which is why idolaters are declared by God to be guilty of spiritual adultery. Through adultery the very source and root of humankind is contaminated; families are broken, as well as the marriage bed; children are badly hurt; public decency is violated; it is a sin against one’s own body; it brings mental blindness and incurs countless dangers; the temple of the Holy Spirit is profaned; and members of the Body of Christ are made members of a whore and an adulteress. The fruits of adultery frequently are homicide and poisoning. This explains why the wisest legislators decree the most serious punishments for adulterers. Suetonius (Vita Julii Caesaris) reports that a freedman very dear to Caesar received capital punishment because he had committed adultery with the wife of a Roman knight, even though no one had made an accusation against him. Julius Capitolinus reports that Emperor Macrinus burned alive those guilty of adultery along with their partners. Vopiscus reports that Emperor Aurelian punished a soldier who had committed adultery with the wife of his host by bending down the tops of two trees, tying them to the feet of the soldier, and then ordering them to be suddenly let go so that the soldier was split apart and hung there in two pieces. Constantine the Great passed a law ordering violators of marriage to be punished by the sword. Justinus recounts that the Parthians avenged no sin more severely than adultery. But where, O Julian law, are you sleeping now?
Whether nocturnal defilement is sin.
§ 165. (IV) The question arises: Is nocturnal defilement sin?
We respond. We are forbidden by modesty to speak in the presence of chaste ears about the sin of onanism [cf. Gen. 38:8–9]. Therefore our inquiry is about that involuntary ejaculation of semen at night, which sometimes happens during sleep.
** Deut. 23:10–11: “If there is among you a man who is unclean by reason of what happens to him by night, then he shall go outside the camp. He shall not come within the camp; but, when evening comes on, he shall bathe himself in water, and when the sun sets, he shall come within the camp.” In regard to this nocturnal defilement, Augustine complains bitterly (Confess., bk. 10, ch. [30]) and offers his opinion (in De Genes., bk. 2, ch. 15; and in De Trinit., bk. 11, ch. 4). **
Jean Gerson, chancellor of the University of Paris, wrote a particular treatise on this subject (Operum, part 2, f. 211), where he forms these propositions:
No defiling begun and finished in sleep is mortal sin because what is involuntary is not a sin. But if someone who is awake should have an impure desire to defile himself and falls asleep while [this desire] is strong, or if he should wake up and wickedly consummate a defiling which began when he was asleep, then that obscene work would be counted to his blame. Likewise, someone could sin afterward by being very pleased by such a shameful pleasure as he had; also by intoxication one could fall into this defilement. Then his being awake rather than being asleep would have the blame.
Gerson adds (consid. 6): “Physical defilement can occur during sleep not only without mortal sin preceding it but even without fault [ex merito]—for example, if it happens to the unwilling and those who fight against it; if it happens as a result of a strict abstinence on bread and water; if while awake one has thought about it for a useful purpose; if it happens by the trickery of a demon; etc.” (See more there in the same place.) Forced virginity, auricular confession, and imposed satisfactions gave rise to such debates.
Under the ceremonial law a man with a seminal discharge was considered unclean (Lev. 15:2). Although it cannot be inferred from this contamination of the [ceremonial] law that it is a sin—because both menstruating women and those who touched a dead person were considered unclean ceremonially and legally—nevertheless, since such a seminal emission occurs very rarely or never without prior, accompanying, or subsequent pleasure, it is safest to recognize this as a sin in the judgment of God, to deplore it, and to use the divinely established remedy of marriage for it. What the Jesuit Toletus claims (nstruct., bk. 5, ch. 13) based on Thomas should be rejected wholeheartedly: “If anyone should desire to have a defilement for a good purpose or because of his health or to alleviate the temptations of the flesh which afflict him at times, that is not a sin.”