Summa - Supplement 1020



We must now consider the impediments to matrimony in particular, and in the first place the impediment of error. Under this head there are two points of inquiry:

(1) Whether error of its very nature is an impediment to matrimony?

(2) What kind of error?

Whether it is right to reckon error as an impediment to marriage?


Objection 1: It would seem that error should not be reckoned in itself an impediment to marriage. For consent, which is the efficient cause of marriage, is hindered in the same way as the voluntary. Now the voluntary, according to the Philosopher (Ethic. iii, 1), may be hindered by ignorance. But ignorance is not the same as error, because ignorance excludes knowledge altogether, whereas error does not, since "error is to approve the false as though it were true," according to Augustine (De Trin. ix, 11). Therefore ignorance rather than error should have been reckoned here as an impediment to marriage.

Objection 2: Further, that which of its very nature can be an impediment to marriage is in opposition to the good of marriage. But error is not a thing of this kind. Therefore error is not by its very nature an impediment to marriage.

Objection 3: Further, just as consent is required for marriage, so is intention required for baptism. Now if one were to baptize John, thinking to baptize Peter, John would be baptized none the less. Therefore error does not annul matrimony.

Objection 4: Further, there was true marriage between Lia and Jacob, and yet, in this case, there was error. Therefore error does not annul a marriage.

On the contrary, It is said in the Digests (Si per errorem, ff. De jurisdic. omn. judic.): "What is more opposed to consent than error?" Now consent is required for marriage. Therefore error is an impediment to matrimony.

Further, consent denotes something voluntary. Now error is an obstacle to the voluntary, since "the voluntary," according to the Philosopher (Ethic. iii, 1), Damascene (De Fide Orth. ii, 24), and Gregory of Nyssa [*Nemesius] (De Nat. Hom. xxxii), "is that which has its principle in one who has knowledge of singulars which are the matter of actions." But this does not apply to one who is in error. Therefore error is an impediment to matrimony.

I answer that, Whatever hinders a cause, of its very nature hinders the effect likewise. Now consent is the cause of matrimony, as stated above (Question [45], Article [1]). Hence whatever voids the consent, voids marriage. Now consent is an act of the will, presupposing an act of the intellect; and if the first be lacking, the second must needs be lacking also. Hence, when error hinders knowledge, there follows a defect in the consent also, and consequently in the marriage. Therefore it is possible according to the natural law for error to void marriage.

Reply to Objection 1: Speaking simply, ignorance differs from error, because ignorance does not of its very nature imply an act of knowledge, while error supposes a wrong judgment of reason about something. However, as regards being an impediment to the voluntary, it differs not whether we call it ignorance or error, since no ignorance can be an impediment to the voluntary, unless it have error in conjunction with it, because the will's act presupposes an estimate or judgment about something which is the object of the will. Wherefore if there be ignorance there must needs be error; and for this reason error is set down as being the proximate cause.

Reply to Objection 2: Although error is not of itself contrary to matrimony, it is contrary thereto as regards the cause of marriage.

Reply to Objection 3: The character of baptism is not caused directly by the intention of the baptizer, but by the material element applied outwardly; and the intention is effective only as directing the material element to its effect; whereas the marriage tie is caused by the consent directly. Hence the comparison fails.

Reply to Objection 4: According to the Master (Sent. iv, D, 30) the marriage between Lia and Jacob was effected not by their coming together, which happened through an error, but by their consent, which followed afterwards. Yet both are clearly to be excused from sin (Sent. iv, D, 30).

Whether every error is an impediment to matrimony?


Objection 1: It would seem that every error is an impediment to matrimony, and not, as stated in the text (Sent. iv, D, 30), only error about the condition or the person. For that which applies to a thing as such applies to it in all its bearings. Now error is of its very nature an impediment to matrimony, as stated above (Article [1]). Therefore every error is an impediment to matrimony.

Objection 2: Further, if error, as such, is an impediment to matrimony, the greater the error the greater the impediment. Now the error concerning faith in a heretic who disbelieves in this sacrament is greater than an error concerning the person. Therefore it should be a greater impediment than error about the person.

Objection 3: Further, error does not void marriage except as removing voluntariness. Now ignorance about any circumstance takes away voluntariness (Ethic. iii, 1). Therefore it is not only error about condition or person that is an impediment to matrimony.

Objection 4: Further, just as the condition of slavery is an accident affecting the person, so are bodily or mental qualities. But error regarding the condition is an impediment to matrimony. Therefore error concerning quality or fortune is equally an impediment.

Objection 5: Further, just as slavery or freedom pertains to the condition of person, so do high and low rank, or dignity of position and the lack thereof. Now error regarding the condition of slavery is an impediment to matrimony. Therefore error about the other matters mentioned is also an impediment.

Objection 6: Further, just as the condition of slavery is an impediment, so are difference of worship and impotence, as we shall say further on (Question [52], Article [2]; Question [58], Article [1]; Question [59], Article [1]). Therefore just as error regarding the condition is an impediment, so also should error about those other matters be reckoned an impediment.

Objection 7: On the other hand, it would seem that not even error about the person is an impediment to marriage. For marriage is a contract even as a sale is. Now in buying and selling the sale is not voided if one coin be given instead of another of equal value. Therefore a marriage is not voided if one woman be taken instead of another.

Objection 8: Further, it is possible for them to remain in this error for many years and to beget between them sons and daughters. But it would be a grave assertion to maintain that they ought to be separated then. Therefore their previous error did not void their marriage.

Objection 9: Further, it might happen that the woman is betrothed to the brother of the man whom she thinks that she is consenting to marry, and that she has had carnal intercourse with him; in which case, seemingly, she cannot go back to the man to whom she thought to give her consent, but should hold on to his brother. Thus error regarding the person is not an impediment to marriage.

I answer that, Just as error, through causing involuntariness, is an excuse from sin, so on the same count is it an impediment to marriage. Now error does not excuse from sin unless it refer to a circumstance the presence or absence of which makes an action lawful or unlawful. For if a man were to strike his father with an iron rod thinking it to be of wood, he is not excused from sin wholly, although perhaps in part; but if a man were to strike his father, thinking to strike his son to correct him, he is wholly excused provided he take due care. Wherefore error, in order to void marriage, must needs be about the essentials of marriage. Now marriage includes two things, namely the two persons who are joined together, and the mutual power over one another wherein marriage consists. The first of these is removed by error concerning the person, the second by error regarding the condition, since a slave cannot freely give power over his body to another, without his master's consent. For this reason these two errors, and no others, are an impediment to matrimony.

Reply to Objection 1: It is not from its generic nature that error is an impediment to marriage, but from the nature of the difference added thereto; namely from its being error about one of the essentials to marriage.

Reply to Objection 2: An error of faith about matrimony is about things consequent upon matrimony, for instance on the question of its being a sacrament, or of its being lawful. Wherefore such error as these is no impediment to marriage, as neither does an error about baptism hinder a man from receiving the character, provided he intend to receive what the Church gives, although he believe it to be nothing.

Reply to Objection 3: It is not any ignorance of a circumstance that causes the involuntariness which is an excuse from sin, as stated above; wherefore the argument does not prove.

Reply to Objection 4: Difference of fortune or of quality does not make a difference in the essentials to matrimony, as the condition of slavery does. Hence the argument does not prove.

Reply to Objection 5: Error about a person's rank, as such, does not void a marriage, for the same reason as neither does error about a personal quality. If, however, the error about a person's rank or position amounts to an error about the person, it is an impediment to matrimony. Hence, if the woman consent directly to this particular person, her error about his rank does not void the marriage; but if she intend directly to consent to marry the king's son, whoever he may be, then, if another man than the king's son be brought to her, there is error about the person, and the marriage will be void.

Reply to Objection 6: Error is an impediment to matrimony, although it be about other impediments to marriage if it concern those things which render a person an unlawful subject of marriage. But (the Master) does not mention error about such things, because they are an impediment to marriage whether there be error about them or not; so that if a woman contract with a subdeacon, whether she know this or not, there is no marriage; whereas the condition of slavery is no impediment if the slavery be known. Hence the comparison fails.

Reply to Objection 7: In contracts money is regarded as the measure of other things (Ethic. v, 5), and not as being sought for its own sake. Hence if the coin paid is not what it is thought to be but another of equal value, this does not void the contract. But if there be error about a thing sought for its own sake, the contract is voided, for instance if one were to sell a donkey for a horse; and thus it is in the case in point.

Reply to Objection 8: No matter how long they have cohabited, unless she be willing to consent again, there is no marriage.

Reply to Objection 9: If she did not consent previously to marry his brother, she may hold to the one whom she took in error. Nor can she return to his brother, especially if there has been carnal intercourse between her and the man she took to husband. If, however, she had previously consented to take the first one in words of the present, she cannot have the second while the first lives. But she may either leave the second or return to the first; and ignorance of the fact excuses her from sin, just as she would be excused if after the consummation of the marriage a kinsman of her husband were to know her by fraud since she is not to be blamed for the other's deceit.



We must now consider the impediment of the condition of slavery. Under this head there are four points of inquiry:

(1) Whether the condition of slavery is an impediment to matrimony?

(2) Whether a slave can marry without his master's consent?

(3) Whether a man who is already married can make himself a slave without his wife's consent?

(4) Whether the children should follow the condition of their father or of their mother?

Whether the condition of slavery is an impediment to matrimony?


Objection 1: It would seem that the condition of slavery is no impediment to matrimony. For nothing is an impediment to marriage except what is in some way opposed to it. But slavery is in no way opposed to marriage, else there could be no marriage among slaves. Therefore slavery is no impediment to marriage.

Objection 2: Further, that which is contrary to nature cannot be an impediment to that which is according to nature. Now slavery is contrary to nature, for as Gregory says (Pastor. ii, 6), "it is contrary to nature for man to wish to lord it over another man"; and this is also evident from the fact that it was said of man (
Gn 1,26) that he should "have dominion over the fishes of the sea," but not that he should have dominion over man. Therefore it cannot be an impediment to marriage, which is a natural thing.

Objection 3: Further, if it is an impediment, this is either of natural law or of positive law. But it is not of natural law, since according to natural law all men are equal, as Gregory says (Pastor. ii, 6), while it is stated at the beginning of the Digests (Manumissiones, ff. de just. et jure.) that slavery is not of natural law; and positive law springs from the natural law, as Tully says (De Invent. ii). Therefore, according to law, slavery is not an impediment to any marriage.

Objection 4: Further, that which is an impediment to marriage is equally an impediment whether it be known or not, as in the case of consanguinity. Now the slavery of one party, if it be known to the other, is no impediment to their marriage. Therefore slavery, considered in itself, is unable to void a marriage; and consequently it should not be reckoned by itself as a distinct impediment to marriage.

Objection 5: Further, just as one may be in error about slavery, so as to deem a person free who is a slave, so may one be in error about freedom, so as to deem a person a slave whereas he is free. But freedom is not accounted an impediment to matrimony. Therefore neither should slavery be so accounted.

Objection 7: Further, leprosy is a greater burden to the fellowship of marriage and is a greater obstacle to the good of the offspring than slavery is. Yet leprosy is not reckoned an impediment to marriage. Therefore neither should slavery be so reckoned.

On the contrary, A Decretal says (De conjug. servorum, cap. Ad nostram) that "error regarding the condition hinders a marriage from being contracted and voids that which is already contracted."

Further, marriage is one of the goods that are sought for their own sake, because it is qualified by honesty; whereas slavery is one of the things to be avoided for their own sake. Therefore marriage and slavery are contrary to one another; and consequently slavery is an impediment to matrimony.

I answer that, In the marriage contract one party is bound to the other in the matter of paying the debt; wherefore if one who thus binds himself is unable to pay the debt, ignorance of this inability, on the side of the party to whom he binds himself, voids the contract. Now just as impotence in respect of coition makes a person unable to pay the debt, so that he is altogether disabled, so slavery makes him unable to pay it freely. Therefore, just as ignorance or impotence in respect of coition is an impediment if not known but not if known, as we shall state further on (Question [58]), so the condition of slavery is an impediment if not known, but not if it be known.

Reply to Objection 1: Slavery is contrary to marriage as regards the act to which marriage binds one party in relation to the other, because it prevents the free execution of that act; and again as regards the good of the offspring who become subject to the same condition by reason of the parent's slavery. Since, however, it is free to everyone to suffer detriment in that which is his due, if one of the parties knows the other to be a slave, the marriage is none the less valid. Likewise since in marriage there is an equal obligation on either side to pay the debt, neither party can exact of the other a greater obligation than that under which he lies; so that if a slave marry a bondswoman, thinking her to be free, the marriage is not thereby rendered invalid. It is therefore evident that slavery is no impediment to marriage except when it is unknown to the other party, even though the latter be in a condition of freedom; and so nothing prevents marriage between slaves, or even between a freeman and a bondswoman.

Reply to Objection 2: Nothing prevents a thing being against nature as to the first intention of nature, and yet not against nature as to its second intention. Thus, as stated in De Coelo, ii, all corruption, defect, and old age are contrary to nature, because nature intends being and perfection, and yet they are not contrary to the second intention of nature, because nature, through being unable to preserve being in one thing, preserves it in another which is engendered of the other's corruption. And when nature is unable to bring a thing to a greater perfection it brings it to a lesser; thus when it cannot produce a male it produces a female which is "a misbegotten male" (De Gener. Animal. ii, 3). I say then in like manner that slavery is contrary to the first intention of nature. Yet it is not contrary to the second, because natural reason has this inclination, and nature has this desire---that everyone should be good; but from the fact that a person sins, nature has an inclination that he should be punished for his sin, and thus slavery was brought in as a punishment of sin. Nor is it unreasonable for a natural thing to be hindered by that which is unnatural in this way; for thus is marriage hindered by impotence of coition, which impotence is contrary to nature in the way mentioned.

Reply to Objection 3: The natural law requires punishment to be inflicted for guilt, and that no one should be punished who is not guilty; but the appointing of the punishment according to the circumstances of person and guilt belongs to positive law. Hence slavery which is a definite punishment is of positive law, and arises out of natural law, as the determinate from that which is indeterminate. And it arises from the determination of the same positive law that slavery if unknown is an impediment to matrimony, lest one who is not guilty be punished; for it is a punishment to the wife to have a slave for husband, and "vice versa."

Reply to Objection 4: Certain impediments render a marriage unlawful; and since it is not our will that makes a thing lawful or unlawful, but the law to which our will ought to be subject, it follows that the validity or invalidity of a marriage is not affected either by ignorance (such as destroys voluntariness) of the impediment or by knowledge thereof; and such an impediment is affinity or a vow, and others of the same kind. other impediments, however, render a marriage ineffectual as to the payment of the debt; and since it is within the competency of our will to remit a debt that is due to us, it follows that such impediments, if known, do not invalidate a marriage, but only when ignorance of them destroys voluntariness. Such impediments are slavery and impotence of coition. And, because they have of themselves the nature of an impediment, they are reckoned as special impediments besides error; whereas a change of person is not reckoned a special impediment besides error, because the substitution of another person has not the nature of an impediment except by reason of the intention of one of the contracting parties.

Reply to Objection 5: Freedom does not hinder the marriage act, wherefore ignorance of freedom is no impediment to matrimony.

Reply to Objection 6: Leprosy does not hinder marriage as to its first act, since lepers can pay the debt freely; although they lay a burden upon marriage as to its secondary effects; wherefore it is not an impediment to marriage as slavery is.

Whether a slave can marry without his master's consent?


Objection 1: It would seem that a slave cannot marry without his master's consent. For no one can give a person that which is another's without the latter's consent. Now a slave is his master's chattel. Therefore he cannot give his wife power over his body by marrying without his master's consent.

Objection 2: Further, a slave is bound to obey his master. But his master may command him not to consent to marry. Therefore he cannot marry without his consent.

Objection 3: Further, after marriage, a slave is bound even by a precept of the Divine law to pay the debt to his wife. But at the time that his wife asks for the debt his master may demand of him a service which he will be unable to perform if he wish to occupy himself in carnal intercourse. Therefore if a slave can marry without his master's consent, the latter would be deprived of a service due to him without any fault of his; and this ought not to be.

Objection 4: Further, a master may sell his slave into a foreign country, where the latter's wife is unable to follow him, through either bodily weakness, or imminent danger to her faith; for instance if he be sold to unbelievers, or if her master be unwilling, supposing her to be a bondswoman; and thus the marriage will be dissolved, which is unfitting. Therefore a slave cannot marry without his master's consent.

Objection 5: Further, the burden under which a man binds himself to the Divine service is more advantageous than that whereby a man subjects himself to his wife. But a slave cannot enter religion or receive orders without his master's consent. Much less therefore can he be married without his consent.

On the contrary, "In Christ Jesus . . . there is neither bond nor free" (
Ga 3,26 Ga 3,28). Therefore both freeman and bondsman enjoy the same liberty to marry in the faith of Christ Jesus.

Further, slavery is of positive law; whereas marriage is of natural and Divine law. Since then positive law is not prejudicial to the natural or the Divine law, it would seem that a slave can marry without his master's consent.

I answer that, As stated above (Article [1], ad 3), the positive law arises out of the natural law, and consequently slavery, which is of positive law, cannot be prejudicious to those things that are of natural law. Now just as nature seeks the preservation of the individual, so does it seek the preservation of the species by means of procreation; wherefore even as a slave is not so subject to his master as not to be at liberty to eat, sleep, and do such things as pertain to the needs of his body, and without which nature cannot be preserved, so he is not subject to him to the extent of being unable to marry freely, even without his master's knowledge or consent.

Reply to Objection 1: A slave is his master's chattel in matters superadded to nature, but in natural things all are equal. Wherefore, in things pertaining to natural acts, a slave can by marrying give another person power over his body without his master's consent.

Reply to Objection 2: A slave is bound to obey his master in those things which his master can command lawfully; and just as his master cannot lawfully command him not to eat or sleep, so neither can he lawfully command him to refrain from marrying. For it is the concern of the lawgiver how each one uses his own, and consequently if the master command his slave not to marry, the slave is not bound to obey his master.

Reply to Objection 3: If a slave has married with his master's consent, he should omit the service commanded by his master and pay the debt to his wife; because the master, by consenting to his slave's marriage, implicitly consented to all that marriage requires. If, however, the marriage was contracted without the master's knowledge or consent, he is not bound to pay the debt, but in preference to obey his master, if the two things are incompatible. Nevertheless in such matters there are many particulars to be considered, as in all human acts, namely the danger to which his wife's chastity is exposed, and the obstacle which the payment of the debt places in the way of the service commanded, and other like considerations, all of which being duly weighed it will be possible to judge which of the two in preference the slave is bound to obey, his master or his wife.

Reply to Objection 4: In such a case it is said that the master should be compelled not to sell the slave in such a way as to increase the weight of the marriage burden, especially since he is able to obtain anywhere a just price for his slave.

Reply to Objection 5: By entering religion or receiving orders a man is bound to the Divine service for all time; whereas a husband is bound to pay the debt to his wife not always, but at a fitting time; hence the comparison fails. Moreover, he who enters religion or receives orders binds himself to works that are superadded to natural works, and in which his master has power over him, but not in natural works to which a man binds himself by marriage. Hence he cannot vow continence without his master's consent.

Whether slavery can supervene to marriage?


Objection 1: It would seem that slavery cannot supervene to marriage, by the husband selling himself to another as slave. Because what is done by fraud and to another's detriment should not hold. But a husband who sells himself for a slave, does so sometimes to cheat marriage, and at least to the detriment of his wife. Therefore such a sale should not hold as to the effect of slavery.

Objection 2: Further, two favorable things outweigh one that is not favorable. Now marriage and freedom are favorable things and are contrary to slavery, which in law is not a favorable thing. Therefore such a slavery ought to be entirely annulled in marriage.

Objection 3: Further, in marriage husband and wife are on a par with one another. Now the wife cannot surrender herself to be a slave without her husband's consent. Therefore neither can the husband without his wife's consent.

Objection 4: Further, in natural things that which hinders a thing being generated destroys it after it has been generated. Now bondage of the husband, if unknown to the wife, is an impediment to the act of marriage before it is performed. Therefore if it could supervene to marriage it would dissolve it; which is unreasonable.

On the contrary, Everyone can give another that which is his own. Now the husband is his own master since he is free. Therefore he can surrender his right to another.

Further, a slave can marry without his master's consent, as stated above (Article [2]). Therefore a husband can in like manner subject himself to a master, without his wife's consent.

I answer that, A husband is subject to his wife in those things which pertain to the act of nature; in these things they are equal, and the subjection of slavery does not extend thereto. Wherefore the husband, without his wife's knowledge, can surrender himself to be another's slave. Nor does this result in a dissolution of the marriage, since no impediment supervening to marriage can dissolve it, as stated above (Question [50], Article [1], ad 7).

Reply to Objection 1: The fraud can indeed hurt the person who has acted fraudulently, but it cannot be prejudicial to another person: wherefore if the husband, to cheat his wife, surrender himself to be another's slave, It will be to his own prejudice, through his losing the inestimable good of freedom; whereas this can nowise be prejudicial to the wife, and he is bound to pay her the debt when she asks, and to do all that marriage requires of him for he cannot be taken away from these obligations by his master's command.

Reply to Objection 2: In so far as slavery is opposed to marriage, marriage is prejudicial to slavery, since the slave is bound then to pay the debt to his wife, though his master be unwilling.

Reply to Objection 3: Although husband and wife are considered to be on a par in the marriage act and in things relating to nature, to which the condition of slavery does not extend, nevertheless as regards the management of the household, and other such additional matters the husband is the head of the wife and should correct her, and not "vice versa." Hence the wife cannot surrender herself to be a slave without her husband's consent.

Reply to Objection 4: This argument considers corruptible things; and yet even in these there are many obstacles to generation that are not capable of destroying what is already generated. But in things which have stability it is possible to have an impediment which prevents a certain thing from beginning to be, yet does not cause it to cease to be; as instanced by the rational soul. It is the same with marriage, which is a lasting tie so long as this life lasts.

Whether children should follow the condition of their father?


Objection 1: It would seem that children should follow the condition of their father. Because dominion belongs to those of higher rank. Now in generating the father ranks above the mother. Therefore, etc.

Objection 2: Further, the being of a thing depends on the form more than on the matter. Now in generation the father gives the form, and the mother the matter (De Gener. Animal. ii, 4). Therefore the child should follow the condition of the father rather than of the mother.

Objection 3: Further, a thing should follow that chiefly to which it is most like. Now the son is more like the father than the mother, even as the daughter is more like the mother. Therefore at least the son should follow the father in preference, and the daughter the mother.

Objection 4: Further, in Holy Writ genealogies are not traced through the women but through the men. Therefore the children follow the father rather than the mother.

On the contrary, If a man sows on another's land, the produce belongs to the owner of the land. Now the woman's womb in relation to the seed of man is like the land in relation to the sower. Therefore, etc.

Further, we observe that in animals born from different species the offspring follows the mother rather that the father, wherefore mules born of a mare and an ass are more like mares than those born of a she-ass and a horse. Therefore it should be the same with men.

I answer that, According to civil law (XIX, ff. De statu hom. vii, cap. De rei vendit.) the offspring follows the womb: and this is reasonable since the offspring derives its formal complement from the father, but the substance of the body from the mother. Now slavery is a condition of the body, since a slave is to the master a kind of instrument in working; wherefore children follow the mother in freedom and bondage; whereas in matters pertaining to dignity as proceeding from a thing's form, they follow the father, for instance in honors, franchise, inheritance and so forth. The canons are in agreement with this (cap. Liberi, 32, qu. iv, in gloss.: cap. Inducens, De natis ex libero ventre) as also the law of Moses (
Ex 21).

In some countries, however, where the civil law does not hold, the offspring follows the inferior condition, so that if the father be a slave the children will be slaves although the mother be free; but not if the father gave himself up as a slave after his marriage and without his wife's consent; and the same applies if the case be reversed. And if both be of servile condition and belong to different masters, the children, if several, are divided among the latter, or if one only, the one master will compensate the other in value and will take the child thus born for his slave. However it is incredible that this custom have as much reason in its favor as the decision of the time-honored deliberations of many wise men. Moreover in natural things it is the rule that what is received is in the recipient according to the mode of the recipient and not according to the mode of the giver; wherefore it is reasonable that the seed received by the mother should be drawn to her condition.

Reply to Objection 1: Although the father is a more noble principle than the mother, nevertheless the mother provides the substance of the body, and it is to this that the condition of slavery attaches.

Reply to Objection 2: As regards things pertaining to the specific nature the son is like the father rather than the mother, but in material conditions should be like the mother rather than the father, since a thing has its specific being from its form, but material conditions from matter.

Reply to Objection 3: The son is like the father in respect of the form which is his, and also the father's, complement. Hence the argument is not to the point.

Reply to Objection 4: It is because the son derives honor from his father rather than from his mother that in the genealogies of Scripture, and according to common custom, children are named after their father rather than from their mother. But in matters relating to slavery they follow the mother by preference.

Summa - Supplement 1020