Summa Theologica, by St. Thomas Aquinas, [1947], at sacred-texts.com
We must now consider the plurality of wives. Under this head there are five points of inquiry:
(1) Whether it is against the natural law to have several wives?
(2) Whether this was ever lawful?
(3) Whether it is against the natural law to have a concubine?
(4) Whether it is a mortal sin to have intercourse with a concubine?
(5) Whether it was ever lawful to have a concubine?
Objection 1: It would seem that it is not against the natural law to have several wives. For custom does not prejudice the law of nature. But "it was not a sin" to have several wives "when this was the custom," according to Augustine (De Bono Conjug. xv) as quoted in the text (Sent. iv, D, 33). Therefore it is not contrary to the natural law to have several wives.
Objection 2: Further, whoever acts in opposition to the natural law, disobeys a commandment, for the law of nature has its commandments even as the written law has. Now Augustine says (De Bono Conjug. xv; De Civ. Dei xv, 38) that "it was not contrary to a commandment" to have several wives, "because by no law was it forbidden." Therefore it is not against the natural law to have several wives.
Objection 3: Further, marriage is chiefly directed to the begetting of offspring. But one man may get children of several women, by causing them to be pregnant. Therefore It is not against the natural law to have several wives.
Objection 4: Further, "Natural right is that which nature has taught all animals," as stated at the beginning of the Digests (1, i, ff. De just. et jure). Now nature has not taught all animals that one male should be united to but one female, since with many animals the one male is united to several females. Therefore it is not against the natural law to have several wives.
Objection 5: Further, according to the Philosopher (De Gener. Animal. i, 20), in the begetting of offspring the male is to the female as agent to patient, and as the craftsman is to his material. But it is not against the order of nature for one agent to act on several patients, or for one craftsman to work in several materials. Therefore neither is it contrary to the law of nature for one husband to have many wives.
Objection 6: On the contrary, That which was instilled into man at the formation of human nature would seem especially to belong to the natural law. Now it was instilled into him at the very formation of human nature that one man should have one wife, according to Gn. 2:24, "They shall be two in one flesh." Therefore it is of natural law.
Objection 7: Further, it is contrary to the law of nature that man should bind himself to the impossible, and that what is given to one should be given to another. Now when a man contracts with a wife, he gives her the power of his body, so that he is bound to pay her the debt when she asks. Therefore it is against the law of nature that he should afterwards give the power of his body to another, because it would be impossible for him to pay both were both to ask at the same time.
Objection 8: Further, "Do not to another what thou wouldst not were done to thyself" [*Cf. Tob. 4:16] is a precept of the natural law. But a husband would by no means be willing for his wife to have another husband. Therefore he would be acting against the law of nature, were he to have another wife in addition.
Objection 9: Further, whatever is against the natural desire is contrary to the natural law. Now a husband's jealousy of his wife and the wife's jealousy of her husband are natural, for they are found in all. Therefore, since jealousy is "love impatient of sharing the beloved," it would seem to be contrary to the natural law that several wives should share one husband.
I answer that, All natural things are imbued with certain principles whereby they are enabled not only to exercise their proper actions, but also to render those actions proportionate to their end, whether such actions belong to a thing by virtue of its generic nature, or by virtue of its specific nature: thus it belongs to a magnet to be borne downwards by virtue of its generic nature, and to attract iron by virtue of its specific nature. Now just as in those things which act from natural necessity the principle of action is the form itself, whence their proper actions proceed proportionately to their end, so in things which are endowed with knowledge the principles of action are knowledge and appetite. Hence in the cognitive power there needs to be a natural concept, and in the appetitive power a natural inclination, whereby the action befitting the genus or species is rendered proportionate to the end. Now since man, of all animals, knows the aspect of the end, and the proportion of the action to the end, it follows that he is imbued with a natural concept, whereby he is directed to act in a befitting manner, and this is called "the natural law" or "the natural right," but in other animals "the natural instinct." For brutes are rather impelled by the force of nature to do befitting actions, than guided to act on their own judgment. Therefore the natural law is nothing else than a concept naturally instilled into man, whereby he is guided to act in a befitting manner in his proper actions, whether they are competent to him by virtue of his generic nature, as, for instance, to beget, to eat, and so on, or belong to him by virtue of his specific nature, as, for instance, to reason and so forth. Now whatever renders an action improportionate to the end which nature intends to obtain by a certain work is said to be contrary to the natural law. But an action may be improportionate either to the principal or to the secondary end, and in either case this happens in two ways. First, on account of something which wholly hinders the end; for instance a very great excess or a very great deficiency in eating hinders both the health of the body, which is the principal end of food, and aptitude for conducting business, which is its secondary end. Secondly, on account of something that renders the attainment of the principal or secondary end difficult, or less satisfactory, for instance eating inordinately in respect of undue time. Accordingly if an action be improportionate to the end, through altogether hindering the principal end directly, it is forbidden by the first precepts of the natural law, which hold the same place in practical matters, as the general concepts of the mind in speculative matters. If, however, it be in any way improportionate to the secondary end, or again to the principal end, as rendering its attainment difficult or less satisfactory, it is forbidden, not indeed by the first precepts of the natural law, but by the second which are derived from the first even as conclusions in speculative matters receive our assent by virtue of self-known principles: and thus the act in question is said to be against the law of nature.
Now marriage has for its principal end the begetting and rearing of children, and this end is competent to man according to his generic nature, wherefore it is common to other animals (Ethic. viii, 12), and thus it is that the "offspring" is assigned as a marriage good. But for its secondary end, as the Philosopher says (Ethic. viii, 12), it has, among men alone, the community of works that are a necessity of life, as stated above (Q[41], A[1]). And in reference to this they owe one another "fidelity" which is one of the goods of marriage. Furthermore it has another end, as regards marriage between believers, namely the signification of Christ and the Church: and thus the "sacrament" is said to be a marriage good. Wherefore the first end corresponds to the marriage of man inasmuch as he is an animal: the second, inasmuch as he is a man; the third, inasmuch as he is a believer. Accordingly plurality of wives neither wholly destroys nor in any way hinders the first end of marriage, since one man is sufficient to get children of several wives, and to rear the children born of them. But though it does not wholly destroy the second end, it hinders it considerably for there cannot easily be peace in a family where several wives are joined to one husband, since one husband cannot suffice to satisfy the requisitions of several wives, and again because the sharing of several in one occupation is a cause of strife: thus "potters quarrel with one another" [*Aristotle, Rhet. ii, 4], and in like manner the several wives of one husband. The third end, it removes altogether, because as Christ is one, so also is the Church one. It is therefore evident from what has been said that plurality of wives is in a way against the law of nature, and in a way not against it.
Reply to Objection 1: Custom does not prejudice the law of nature as regards the first precepts of the latter, which are like the general concepts of the mind in speculative matters. But those which are drawn like conclusions from these custom enforces, as Tully declares (De Inv. Rhet. ii), or weakens. Such is the precept of nature in the matter of having one wife.
Reply to Objection 2: As Tully says (De Inv. Rhet. ii), "fear of the law and religion have sanctioned those things that come from nature and are approved by custom." Wherefore it is evident that those dictates of the natural law, which are derived from the first principles as it were of the natural law, have not the binding force of an absolute commandment, except when they have been sanctioned by Divine or human law. This is what Augustine means by saying that "they did not disobey the commandments of the law, since it was not forbidden by any law."
The Reply to the Third Objection follows from what has been said.
Reply to Objection 4: Natural right has several significations. First a right is said to be natural by its principle, because it is instilled by nature: and thus Tully defines it (De Inv. Rhet. ii) when he says: "Natural right is not the result of opinion but the product of an innate force." And since even in natural things certain movements are called natural, not that they be from an intrinsic principle, but because they are from a higher moving principle---thus the movements that are caused in the elements by the impress of heavenly bodies are said to be natural, as the Commentator states (De Coelo et Mundo iii, 28), therefore those things that are of Divine right are said to be of natural right, because they are caused by the impress and influence of a higher principle, namely God. Isidore takes it in this sense, when he says (Etym. v) that "the natural right is that which is contained in the Law and the Gospel." Thirdly, right is said to be natural not only from its principle but also from its matter, because it is about natural things. And since nature is contradistinguished with reason, whereby man is a man, it follows that if we take natural right in its strictest sense, those things which are dictated by natural reason and pertain to man alone are not said to be of natural right, but only those which are dictated by natural reason and are common to man and other animals. Thus we have the aforesaid definition, namely: "Natural right is what nature has taught all animals." Accordingly plurality of wives, though not contrary to natural right taken in the third sense, is nevertheless against natural right taken in the second sense, because it is forbidden by the Divine law. It is also against natural right taken in the first sense, as appears from what has been said, for such is nature's dictate to every animal according to the mode befitting its nature. Wherefore also certain animals, the rearing of whose offspring demands the care of both, namely the male and female, by natural instinct cling to the union of one with one, for instance the turtle-dove, the dove, and so forth.
The Reply to the Fifth Objection is clear from what has been said.
Since, however, the arguments adduced "on the contrary side" would seem to show that plurality of wives is against the first principles of the natural law, we must reply to them.
Accordingly we reply to the Sixth Objection that human nature was founded without any defect, and consequently it is endowed not only with those things without which the principal end of marriage is impossible of attainment, but also with those without which the secondary end of marriage could not be obtained without difficulty: and in this way it sufficed man when he was first formed to have one wife, as stated above.
Reply to Objection 7: In marriage the husband gives his wife power of his body, not in all respects, but only in those things that are required by marriage. Now marriage does not require the husband to pay the debt every time his wife asks for it, if we consider the principal end for which marriage was instituted, namely the good of the offspring, but only as far as is necessary for impregnation. But in so far as it is instituted as a remedy (which is its secondary end), marriage does require the debt to be paid at all times on being asked for. Hence it is evident that by taking several wives a man does not bind himself to the impossible, considering the principal end of marriage; and therefore plurality of wives is not against the first principles of the natural law.
Reply to Objection 8: This precept of the natural law, "Do not to another what thou wouldst not were done to thyself," should be understood with the proviso that there be equal proportion. For if a superior is unwilling to be withstood by his subject, he is not therefore bound not to withstand his subject. Hence it does not follow in virtue of this precept that as a husband is unwilling for his wife to have another husband, he must not have another wife: because for one man to have several wives is not contrary to the first principles of the natural law, as stated above: whereas for one wife to have several husbands is contrary to the first principles of the natural law, since thereby the good of the offspring which is the principal end of marriage is, in one respect, entirely destroyed, and in another respect hindered. For the good of the offspring means not only begetting, but also rearing. Now the begetting of offspring, though not wholly voided (since a woman may be impregnated a second time after impregnation has already taken place, as stated in De Gener. Animal. vii. 4), is nevertheless considerably hindered, because this can scarcely happen without injury either to both fetus or to one of them. But the rearing of the offspring is altogether done away, because as a result of one woman having several husbands there follows uncertainty of the offspring in relation to its father, whose care is necessary for its education. Wherefore the marriage of one wife with several husbands has not been sanctioned by any law or custom, whereas the converse has been.
Reply to Objection 9: The natural inclination in the appetitive power follows the natural concept in the cognitive power. And since it is not so much opposed to the natural concept for a man to have several wives as for a wife to have several husbands, it follows that a wife's love is not so averse to another sharing the same husband with her, as a husband's love is to another sharing the same wife with him. Consequently both in man and in other animals the male is more jealous of the female than "vice versa."
Objection 1: It would seem that it can never have been lawful to have several wives. For, according to the Philosopher (Ethic. v, 7), "The natural law has the same power at all times and places." Now plurality of wives is forbidden by the natural law, as stated above (A[1]). Therefore as it is unlawful now, it was unlawful at all times.
Objection 2: Further, if it was ever lawful, this could only be because it was lawful either in itself, or by dispensation. If the former, it would also be lawful now; if the latter, this is impossible, for according to Augustine (Contra Faust. xxvi, 3), "as God is the founder of nature, He does nothing contrary to the principles which He has planted in nature." Since then God has planted in our nature the principle that one man should be united to one wife, it would seem that He has never dispensed man from this.
Objection 3: Further, if a thing be lawful by dispensation, it is only lawful for those who receive the dispensation. Now we do not read in the Law of a general dispensation having been granted to all. Since then in the Old Testament all who wished to do so, without any distinction, took to themselves several wives, nor were reproached on that account, either by the law or by the prophets, it would seem that it was not made lawful by dispensation.
Objection 4: Further, where there is the same reason for dispensation, the same dispensation should be given. Now we cannot assign any other reason for dispensation than the multiplying of the offspring for the worship of God, and this is necessary also now. Therefore this dispensation would be still in force, especially as we read nowhere of its having been recalled.
Objection 5: Further, in granting a dispensation the greater good should not be overlooked for the sake of a lesser good. Now fidelity and the sacrament, which it would seem impossible to safeguard in a marriage where one man is joined to several wives, are greater goods than the multiplication of the offspring. Therefore this dispensation ought not to have been granted with a view to this multiplication.
On the contrary, It is stated (Gal. 3:19) that the Law "was set because of transgressors [Vulg.: 'transgressions']," namely in order to prohibit them. Now the Old Law mentions plurality of wives without any prohibition thereof, as appears from Dt. 21:15, "If a man have two wives," etc. Therefore they were not transgressors through having two wives; and so it was lawful.
Further, this is confirmed by the example of the holy patriarchs, who are stated to have had several wives, and yet were most pleasing to God, for instance Jacob, David, and several others. Therefore at one time it was lawful.
I answer that, As stated above (A[1], ad 7,8), plurality of wives is said to be against the natural law, not as regards its first precepts, but as regards the secondary precepts, which like conclusions are drawn from its first precepts. Since, however, human acts must needs vary according to the various conditions of persons, times, and other circumstances, the aforesaid conclusions do not proceed from the first precepts of the natural law, so as to be binding in all cases, but only in the majority. for such is the entire matter of Ethics according to the Philosopher (Ethic. i, 3,7). Hence, when they cease to be binding, it is lawful to disregard them. But because it is not easy to determine the above variations, it belongs exclusively to him from whose authority he derives its binding force to permit the non-observance of the law in those cases to which the force of the law ought not to extend, and this permission is called a dispensation. Now the law prescribing the one wife was framed not by man but by God, nor was it ever given by word or in writing, but was imprinted on the heart, like other things belonging in any way to the natural law. Consequently a dispensation in this matter could be granted by God alone through an inward inspiration, vouchsafed originally to the holy patriarchs, and by their example continued to others, at a time when it behooved the aforesaid precept not to be observed, in order to ensure the multiplication of the offspring to be brought up in the worship of God. For the principal end is ever to be borne in mind before the secondary end. Wherefore, since the good of the offspring is the principal end of marriage, it behooved to disregard for a time the impediment that might arise to the secondary ends, when it was necessary for the offspring to be multiplied; because it was for the removal of this impediment that the precept forbidding a plurality of wives was framed, as stated above (A[1]).
Reply to Objection 1: The natural law, considered in itself, has the same force at all times and places; but accidentally on account of some impediment it may vary at certain times and places, as the Philosopher (Ethic. i, 3,7) instances in the case of other natural things. For at all times and places the right hand is better than the left according to nature, but it may happen accidentally that a person is ambidextrous, because our nature is variable; and the same applies to the natural, just as the Philosopher states (Ethic. i, 3,7).
Reply to Objection 2: In a Decretal (De divortiis, cap. Gaudemus) it is asserted that is was never lawful to have several wives without having a dispensation received through Divine inspiration. Nor is the dispensation thus granted a contradiction to the principles which God has implanted in nature, but an exception to them, because those principles are not intended to apply to all cases but to the majority, as stated. Even so it is not contrary to nature when certain occurrences take place in natural things miraculously, by way of exception to more frequent occurrences.
Reply to Objection 3: Dispensation from a law should follow the quality of the law. Wherefore, since the law of nature is imprinted on the heart, it was not necessary for a dispensation from things pertaining to the natural law to be given under the form of a written law but by internal inspiration.
Reply to Objection 4: When Christ came it was the time of the fulness of the grace of Christ, whereby the worship of God was spread abroad among all nations by a spiritual propagation. Hence there is not the same reason for a dispensation as before Christ's coming, when the worship of God was spread and safeguarded by a carnal propagation.
Reply to Objection 5: The offspring, considered as one of the marriage goods, includes the keeping of faith with God, because the reason why it is reckoned a marriage good is because it is awaited with a view to its being brought up in the worship of God. Now the faith to be kept with God is of greater import than the faith to be kept with a wife, which is reckoned a marriage good, and than the signification which pertains to the sacrament, since the signification is subordinate to the knowledge of faith. Hence it is not unfitting if something is taken from the two other goods for the sake of the good of the offspring. Nor are they entirely done away, since there remains faith towards several wives; and the sacrament remains after a fashion, for though it did not signify the union of Christ with the Church as one, nevertheless the plurality of wives signified the distinction of degrees in the Church, which distinction is not only in the Church militant but also in the Church triumphant. Consequently their marriages signified somewhat the union of Christ not only with the Church militant, as some say, but also with the Church triumphant where there are "many mansions" [*Jn. 19:2].
Objection 1: It would seem that to have a concubine is not against the natural law. For the ceremonies of the Law are not of the natural law. But fornication is forbidden (Acts 15:29) in conjunction with ceremonies of the law which for the time were being imposed on those who were brought to the faith from among the heathens. Therefore simple fornication which is intercourse with a concubine is not against the natural law.
Objection 2: Further, positive law is an outcome of the natural law, as Tully says (De Invent. ii). Now fornication was not forbidden by positive law; indeed according to the ancient laws women used to be sentenced to be taken to brothels. Therefore it is not against the natural law to have a concubine.
Objection 3: Further, the natural law does not forbid that which is given simply, to be given for a time or under certain restrictions. Now one unmarried woman may give the power of her body for ever to an unmarried man, so that he may use her when he will. Therefore it is not against the law of nature, if she give him power of her body for a time.
Objection 4: Further, whoever uses his own property as he will, injures no one. But a bondswoman is her master's property. Therefore if her master use her as he will, he injures no one: and consequently it is not against the natural law to have a concubine.
Objection 5: Further, everyone may give his own property to another. Now the wife has power of her husband's body (1 Cor. 7:4). Therefore if his wife be willing, the husband can have intercourse with another woman without sin.
On the contrary, According to all laws the children born of a concubine are children of shame. But this would not be so unless the union of which they are born were naturally shameful.
Further, as stated above (Q[41], A[1]), marriage is natural. But this would not be so if without prejudice to the natural law a man could be united to a woman otherwise than by marriage. Therefore it is against the natural law to have a concubine.
I answer that, As stated above (A[1]), an action is said to be against the natural law, if it is not in keeping with the due end intended by nature, whether through not being directed thereto by the action of the agent, or through being directed thereto by the action of the agent, or through being in itself improportionate to that end. Now the end which nature intends in sexual union is the begetting and rearing of the offspring. and that this good might be sought after, it attached pleasure to the union; as Augustine says (De Nup. et Concup. i, 8). Accordingly to make use of sexual intercourse on account of its inherent pleasure, without reference to the end for which nature intended it, is to act against nature, as also is it if the intercourse be not such as may fittingly be directed to that end. And since, for the most part, things are denominated from their end, as being that which is of most consequence to them, just as the marriage union took its name from the good of the offspring [*Cf. Q[44], A[2]], which is the end chiefly sought after in marriage, so the name of concubine is expressive of that union where sexual intercourse is sought after for its own sake. Moreover even though sometimes a man may seek to have offspring of such an intercourse, this is not befitting to the good of the offspring, which signifies not only the begetting of children from which they take their being, but also their rearing and instruction, by which means they receive nourishment and learning from their parents, in respect of which three things the parents are bound to their children, according to the Philosopher (Ethic. viii, 11,12). Now since the rearing and teaching of the children remain a duty of the parents during a long period of time, the law of nature requires the father and mother to dwell together for a long time, in order that together they may be of assistance to their children. Hence birds that unite together in rearing their young do not sever their mutual fellowship from the time when they first come together until the young are fully fledged. Now this obligation which binds the female and her mate to remain together constitutes matrimony. Consequently it is evident that it is contrary to the natural law for a man to have intercourse with a woman who is not married to him, which is the signification of a concubine.
Reply to Objection 1: Among the Gentiles the natural law was obscured in many points: and consequently they did not think it wrong to have intercourse with a concubine, and in many cases practiced fornication as though it were lawful, as also other things contrary to the ceremonial laws of the Jews, though not contrary to the law of nature. Wherefore the apostles inserted the prohibition of fornication among that of other ceremonial observances, because in both cases there was a difference of opinion between Jews and Gentiles.
Reply to Objection 2: This law was the result of the darkness just mentioned, into which the Gentiles had fallen, by not giving due honor to God as stated in Rom. 1:21, and did not proceed from the instinct of the natural law. Hence, when the Christian religion prevailed, this law was abolished.
Reply to Objection 3: In certain cases no evil results ensue if a person surrenders his right to a thing whether absolutely or for a time, so that in neither case is the surrender against the natural law. But that does not apply to the case in point, wherefore the argument does not prove.
Reply to Objection 4: Injury is opposed to justice. Now the natural law forbids not only injustice, but also whatever is opposed to any of the virtues: for instance it is contrary to the natural law to eat immoderately, although by doing so a man uses his own property without injury to anyone. Moreover although a bondswoman is her master's property that she may serve him, she is not his that she may be his concubine. And again it depends how a person makes use of his property. For such a man does an injury to the offspring he begets, since such a union is not directed to its good, as stated above.
Reply to Objection 5: The wife has power of her husband's body, not simply and in all respects, but only in relation to marriage, and consequently she cannot transfer her husband's body to another to the detriment of the good of marriage.
Objection 1: It would seem that it is not a mortal sin to have intercourse with a concubine. For a lie is a greater sin than simple fornication: and a proof of this is that Juda, who did not abhor to commit fornication with Thamar, recoiled from telling a lie, saying (Gn. 38:23): "Surely she cannot charge us with a lie." But a lie is not always a mortal sin. Neither therefore is simple fornication.
Objection 2: Further, a deadly sin should be punished with death. But the Old Law did not punish with death intercourse with a concubine, save in a certain case (Dt. 22:25). Therefore it is not a deadly sin.
Objection 3: Further, according to Gregory (Moral. xxxiii, 12), the sins of the flesh are less blameworthy than spiritual sins. Now pride and covetousness, which are spiritual sins, are not always mortal sins. Therefore fornication, which is a sin of the flesh, is not always a mortal sin.
Objection 4: Further, where the incentive is greater the sin is less grievous, because he sins more who is overcome by a lighter temptation. But concupiscence is the greatest incentive to lust. Therefore since lustful actions are not always mortal sins, neither is simple fornication a mortal sin.
On the contrary, Nothing but mortal sin excludes from the kingdom of God. But fornicators are excluded from the kingdom of God (1 Cor. 6:9, 10). Therefore simple fornication is a mortal sin.
Further, mortal sins alone are called crimes. Now all fornication is a crime according to Tob. 4:13, "Take heed to keep thyself . . . from all fornication, and beside thy wife never endure to know crime." Therefore, etc.
I answer that, As we have already stated (Sent. ii, D, 42, Q[1], A[4]), those sins are mortal in their genus which violate the bond of friendship between man and God, and between man and man; for such sins are against the two precepts of charity which is the life of the soul. Wherefore since the intercourse of fornication destroys the due relations of the parent with the offspring that is nature's aim in sexual intercourse, there can be no doubt that simple fornication by its very nature is a mortal sin even though there were no written law.
Reply to Objection 1: It often happens that a man who does not avoid a mortal sin, avoids a venial sin to which he has not so great an incentive. Thus, too, Juda avoided a lie while he avoided not fornication. Nevertheless that would have been a pernicious lie, for it would have involved an injury if he had not kept his promise.
Reply to Objection 2: A sin is called deadly, not because it is punished with temporal, but because it is punished with eternal death. Hence also theft, which is a mortal sin, and many other sins are sometimes not punished with temporal death by the law. The same applies to fornication.
Reply to Objection 3: Just as not every movement of pride is a mortal sin, so neither is every movement of lust, because the first movements of lust and the like are venial sins, even sometimes marriage intercourse. Nevertheless some acts of lust are mortal sins, while some movements of pride are venial: since the words quoted from Gregory are to be understood as comparing vices in their genus and not in their particular acts.
Reply to Objection 4: A circumstance is the more effective in aggravating a sin according as it comes nearer to the nature of sin. Hence although fornication is less grave on account of the greatness of its incentive, yet on account of the matter about which it is, it has a greater gravity than immoderate eating, because it is about those things which tighten the bond of human fellowship, as stated above. Hence the argument does not prove.
Objection 1: It would seem that it has been sometimes lawful to have a concubine. For just as the natural law requires a man to have but one wife, so does it forbid him to have a concubine. Yet at times it has been lawful to have several wives. Therefore it has also been lawful to have a concubine.
Objection 2: Further, a woman cannot be at the same time a slave and a wife; wherefore according to the Law (Dt. 21:11, seqq.) a bondswoman gained her freedom by the very fact of being taken in marriage. Now we read that certain men who were most beloved of God, for instance Abraham and Jacob, had intercourse with their bondswomen. Therefore these were not wives, and consequently it was sometime lawful to have a concubine.
Objection 3: Further, a woman who is taken in marriage cannot be cast out, and her son should have a share in the inheritance. Yet Abraham sent Agar away, and her son was not his heir (Gn. 21:14). Therefore she was not Abraham's wife.
On the contrary, Things opposed to the precepts of the decalogue were never lawful. Now to have a concubine is against a precept of the decalogue, namely, "Thou shalt not commit adultery." Therefore it was never lawful.
Further, Ambrose says in his book on the patriarchs (De Abraham i, 4): "What is unlawful to a wife is unlawful to a husband." But it is never lawful for a wife to put aside her own husband and have intercourse with another man. Therefore it was never lawful for a husband to have a concubine.
I answer that, Rabbi Moses says (Doc. Perp. iii, 49) that before the time of the Law fornication was not a sin; and he proved his assertion from the fact that Juda had intercourse with Thamar. But this argument is not conclusive. For there is no need to excuse Jacob's sons from mortal sin, since they were accused to their father of a most wicked crime (Gn. 37:2), and consented kill Joseph and to sell him. Wherefore we must say that since it is against the natural law to have a concubine outside wedlock, as stated above (A[3]), it was never lawful either in itself or by dispensation. For as we have shown (Doc. Perp. iii, 49) intercourse with a woman outside wedlock is an action improportionate to the good of the offspring which is the principal end of marriage: and consequently it is against the first precepts of the natural law which admit of no dispensation. Hence wherever in the Old Testament we read of concubines being taken by such men as we ought to excuse from mortal sin, we must needs understand them to have been taken in marriage, and yet to have been called concubines, because they had something of the character of a wife and something of the character of a concubine. In so far as marriage is directed to its principal end, which is the good of the offspring, the union of wife and husband is indissoluble or at least of a lasting nature, as shown above (A[1]), and in regard to this there is no dispensation. But in regard to the secondary end, which is the management of the household and community of works, the wife is united to the husband as his mate: and this was lacking in those who were known as concubines. For in this respect a dispensation was possible, since it is the secondary end of marriage. And from this point of view they bore some resemblance to concubines, and for this reason they were known as such.
Reply to Objection 1: As stated above (A[1], ad 7,8) to have several wives is not against the first precepts of the natural law, as it is to have a concubine; wherefore the argument does not prove.
Reply to Objection 2: The patriarchs of old by virtue of the dispensation which allowed them several wives, approached their bondswomen with the disposition of a husband towards his wife. For these women were wives as to the principal and first end of marriage, but not as to the other union which regards the secondary end, to which bondage is opposed since a woman cannot be at once mate and slave.
Reply to Objection 3: As in the Mosaic law it was allowable by dispensation to grant a bill of divorce in order to avoid wife-murder (as we shall state further on, Q[67], A[6]), so by the same dispensation Abraham was allowed to send Agar away, in order to signify the mystery which the Apostle explains (Gal. 4:22, seqq.). Again, that this son did not inherit belongs to the mystery, as explained in the same place. Even so Esau, the son of a free woman, did not inherit (Rom. 9:13, seqq.). In like manner on account of the mystery it came about that the sons of Jacob born of bond and free women inherited, as Augustine says (Tract. xi in Joan.) because "sons and heirs are born to Christ both of good ministers denoted by the free woman and of evil ministers denoted by the bondswoman."