Summa Th. II-II EN Qu.100 a.4

Whether it is lawful to receive money for things annexed to spiritual things?

Objection: 1. It would seem lawful to receive money for things annexed to spiritual things. Seemingly all temporal things are annexed to spiritual things, since temporal things ought to be sought for the sake of spiritual things. If, therefore, it is unlawful to sell what is annexed to spiritual things, it will be unlawful to sell anything temporal, and this is clearly false.
2. Further, nothing would seem to be more annexed to spiritual things than consecrated vessels. Yet it is lawful to sell a chalice for the ransom of prisoners, according to Ambrose (De Offic. ii, 28). Therefore it is lawful to sell things annexed to spiritual things.
3. Further, things annexed to spiritual things include right of burial, right of patronage, and, according to ancient writers, right of the first-born (because before the Lord the first-born exercised the priestly office), and the right to receive tithes. Now Abraham bought from Ephron a double cave for a burying-place (Gn 23,8, sqq.), and Jacob bought from Esau the right of the first-born (Gn 25,31, sqq.). Again the right of patronage is transferred with the property sold, and is granted "in fee." Tithes are granted to certain soldiers, and can be redeemed. Prelates also at times retain for themselves the revenues of prebends of which they have the presentation, although a prebend is something annexed to a spiritual thing. Therefore it is lawful to sell things annexed to spiritual things.

On the contrary Pope Paschal [*Paschal II] says (cf. I, qu. iii, cap. Si quis objecerit): "Whoever sells one of two such things, that the one is unproductive without the other, leaves neither unsold. Wherefore let no person sell a church, or a prebend, or anything ecclesiastical."
I answer that A thing may be annexed to spiritual things in two ways. First, as being dependent on spiritual things. Thus to have to spiritual things, because it is not competent save to those who hold a clerical office. Hence such things can by no means exist apart from spiritual things. Consequently it is altogether unlawful to sell such things, because the sale thereof implies the sale of things spiritual. Other things are annexed to spiritual things through being directed thereto, for instance the right of patronage, which is directed to the presentation of clerics to ecclesiastical benefices; and sacred vessels, which are directed to the use of the sacraments. Wherefore such things as these do not presuppose spiritual things, but precede them in the order of time. Hence in a way they can be sold, but not as annexed to spiritual things.

Reply to Objection: 1. All things temporal are annexed to spiritual things, as to their end, wherefore it is lawful to sell temporal things, but their relation to spiritual things cannot be the matter of a lawful sale.
2. Sacred vessels also are annexed to spiritual things as to their end, wherefore their consecration cannot be sold. Yet their material can be sold for the needs of the Church or of the poor provided they first be broken, after prayer has been said over them, since when once broken, they are considered to be no longer sacred vessels but mere metal: so that if like vessels were to be made out of the same material they would have to be consecrated again.
3. We have no authority for supposing that the double cave which Abraham bought for a burial place was consecrated for that purpose: wherefore Abraham could lawfully buy that site to be used for burial, in order to turn it into a sepulchre: even so it would be lawful now to buy an ordinary field as a site for a cemetery or even a church. Nevertheless because even among the Gentiles burial places are looked upon as religious, if Ephron intended to accept the price as payment for a burial place, he sinned in selling, though Abraham did not sin in buying, because he intended merely to buy an ordinary plot of ground. Even now, it is lawful in a case of necessity to sell or buy land on which there has previously been a church, as we have also said with regard to sacred vessels (Reply Objection [2]). Or again, Abraham is to be excused because he thus freed himself of a grievance. For although Ephron offered him the burial place for nothing, Abraham deemed that he could not accept it gratis without prejudice to himself.The right of the first-born was due to Jacob by reason of God's choice, according to Ml 1,2-3, "I have loved Jacob, but have hated Esau." Wherefore Esau sinned by selling his birthright, yet Jacob sinned not in buying, because he is understood to have freed himself of his grievance.The right of patronage cannot be the matter of a direct sale, nor can it be granted "in fee," but is transferred with the property sold or granted.The spiritual right of receiving tithes is not granted to layfolk, but merely the temporal commodities which are granted in the name of tithe, as stated above (Question [87], Article [3]).With regard to the granting of benefices it must, however, be observed, that it is not unlawful for a bishop, before presenting a person to a benefice, to decide, for some reason, to retain part of the revenues of the benefice in question, and to spend it on some pious object. But, on the other hand, if he were to require part of the revenues of that benefice to be given to him by the beneficiary, it would be the same as though he demanded payment from him, and he would not escape the guilt of simony.

Whether it is lawful to grant spiritual things in return for an equivalent of service, or for an oral remuneration?

Objection: 1. It would seem that it is lawful to grant spiritual things in return for an equivalent of service, or an oral remuneration. Gregory says (Regist. iii, ep. 18): "It is right that those who serve the interests of the Church should be rewarded." Now an equivalent of service denotes serving the interests of the Church. Therefore it seems lawful to confer ecclesiastical benefices for services received.
2. Further, to confer an ecclesiastical benefice for service received seems to indicate a carnal intention, no less than to do so on account of kinship. Yet the latter seemingly is not simoniacal since it implies no buying or selling. Therefore neither is the former simoniacal.
3. Further, that which is done only at another's request would seem to be done gratis: so that apparently it does not involve simony, which consists in buying or selling. Now oral remuneration denotes the conferring of an ecclesiastical benefice at some person's request. Therefore this is not simoniacal.
4. Further, hypocrites perform spiritual deeds in order that they may receive human praise, which seems to imply oral remuneration: and yet hypocrites are not said to be guilty of simony. Therefore oral remuneration does not entail simony.

On the contrary Pope Urban [*Urban II, Ep. xvii ad Lucium] says: "Whoever grants or acquires ecclesiastical things, not for the purpose for which they were instituted but for his own profit, in consideration of an oral remuneration or of an equivalent in service rendered or money received, is guilty of simony."
I answer that As stated above (Article [2]), the term "money" denotes "anything that can have a pecuniary value." Now it is evident that a man's service is directed to some kind of usefulness, which has a pecuniary value, wherefore servants are hired for a money wage. Therefore to grant a spiritual thing for a service rendered or to be rendered is the same as to grant it for the money, received or promised, at which that service could be valued. If likewise, to grant a person's request for the bestowal of a temporary favor is directed to some kind of usefulness which has a pecuniary value. Wherefore just as a man contracts the guilt of simony by accepting money or any eternal thing which comes under the head of "real remuneration," so too does he contract it, by receiving "oral remuneration" or an "equivalent in service rendered."

Reply to Objection: 1. If a cleric renders a prelate a lawful service, directed to spiritual things (e.g. to the good of the Church, or benefit of her ministers), he becomes worthy of an ecclesiastical benefice by reason of the devotion that led him to render the service, as he would by reason of any other good deed. Hence this is not a case of remuneration for service rendered, such as Gregory has in mind. But if the service be unlawful, or directed to carnal things (e.g. a service rendered to the prelate for the profit of his kindred, or the increase of his patrimony, or the like), it will be a case of remuneration for service rendered, and this will be simony.
2. The bestowal of a spiritual thing gratis on a person by reason of kinship or of any carnal affection is unlawful and carnal, but not simoniacal: since nothing is received in return, wherefore it does not imply a contract of buying and selling, on which simony is based. But to present a person to an ecclesiastical benefice with the understanding or intention that he provide for one's kindred from the revenue is manifest simony.
3. Oral remuneration denotes either praise that pertains to human favor, which has its price, or a request whereby man's favor is obtained or the contrary avoided. Hence if one intend this chiefly one commits simony. Now to grant a request made for an unworthy person implies, seemingly, that this is one's chief intention wherefore the deed itself is simoniacal. But if the request be made for a worthy person, the deed itself is not simoniacal, because it is based on a worthy cause, on account of which a spiritual thing is granted to the person for whom the request is made. Nevertheless there may be simony in the intention, if one look, not to the worthiness of the person, but to human favor. If, however, a person asks for himself, that he may obtain the cure of souls, his very presumption renders him unworthy, and so his request is made for an unworthy person. But, if one be in need, one may lawfully seek for oneself an ecclesiastical benefice without the cure of souls.
4. A hypocrite does not give a spiritual thing for the sake of praise, he only makes a show of it, and under false pretenses stealthily purloins rather than buys human praise: so that seemingly the hypocrite is not guilty of simony.

Whether those who are guilty of simony are fittingly punished by being deprived of what they have acquired by simony?

Objection: 1. It would seem that those who are guilty of simony are not fittingly punished by being deprived of what they have acquired by simony. Simony is committed by acquiring spiritual things in return for a remuneration. Now certain spiritual things cannot be lost when once acquired, such as all characters that are imprinted by a consecration. Therefore it is not a fitting punishment for a person to be deprived of what he has acquired simoniacally.
2. Further, it sometimes happens that one who has obtained the episcopate by simony commands a subject of his to receive orders from him: and apparently the subject should obey, so long as the Church tolerates him. Yet no one ought to receive from him that has not the power to give. Therefore a bishop does not lose his episcopal power, if he has acquired it by simony.
3. Further, no one should be punished for what was done without his knowledge and consent, since punishment is due for sin which is voluntary, as was shown above (FS, Question [74], Articles [1],2; FS, Question [77], Article [7]). Now it happens sometimes that a person acquires something spiritual, which others have procured for him without his knowledge and consent. Therefore he should not be punished by being deprived of what has been bestowed on him.
4. Further, no one should profit by his own sin. Yet, if a person who has acquired an ecclesiastical benefice by simony, were to restore what he has received, this would sometimes turn to the profit of those who had a share in his simony; for instance, when a prelate and his entire chapter have consented to the simony. Therefore that which has been acquired by simony ought not always to be restored.
5. Further, sometimes a person obtains admission to a monastery by simony, and there takes the solemn vow of profession. But no one should be freed from the obligation of a vow on account of a fault he has committed. Therefore he should not be expelled from the monastic state which he has acquired by simony.
6. Further, in this world external punishment is not inflicted for the internal movements of the heart, whereof God alone is the judge. Now simony is committed in the mere intention or will, wherefore it is defined in reference to the will, as stated above (Article [1], ad 2). Therefore a person should not always be deprived of what he has acquired by simony.
7. Further, to be promoted to greater dignity is much less than to retain that which one has already received. Now sometimes those who are guilty of simony are, by dispensation, promoted to greater dignity. Therefore they should not always be deprived of what they have received.

On the contrary It is written (I, qu. i, cap. Si quis Episcopus): "He that has been ordained shall profit nothing from his ordination or promotion that he has acquired by the bargain, but shall forfeit the dignity or cure that he has acquired with his money."
I answer that No one can lawfully retain that which he has acquired against the owner's will. For instance, if a steward were to give some of his lord's property to a person, against his lord's will and orders, the recipient could not lawfully retain what he received. Now Our Lord, Whose stewards and ministers are the prelates of churches, ordered spiritual things to be given gratis, according to Mt 10,8, "Freely have you received, freely give." Wherefore whosoever acquires spiritual things in return for a remuneration cannot lawfully retain them. Moreover, those who are guilty of simony, by either selling or buying spiritual things, as well as those who act as go-between, are sentenced to other punishments, namely, infamy and deposition, if they be clerics, and excommunication if they be laymen, as stated qu. i, cap. Si quis Episcopus [*Qu. iii, can. Si quis praebendas].

Reply to Objection: 1. He that has received a sacred Order simoniacally, receives the character of the Order on account of the efficacy of the sacrament: but he does not receive the grace nor the exercise of the Order, because he has received the character by stealth as it were, and against the will of the Supreme Lord. Wherefore he is suspended, by virtue of the law, both as regards himself, namely, that he should not busy himself about exercising his Order, and as regards others, namely, that no one may communicate with him in the exercise of his Order, whether his sin be public or secret. Nor may he reclaim the money which he basely gave, although the other party unjustly retains it.Again, a man who is guilty of simony, through having conferred Orders simoniacally, or through having simoniacally granted or received a benefice, or through having been a go-between in a simoniacal transaction, if he has done so publicly, is suspended by virtue of the law, as regards both himself and others; but if he has acted in secret he is suspended by virtue of the law, as regards himself alone, and not as regards others.
2. One ought not to receive Orders from a bishop one knows to have been promoted simoniacally, either on account of his command or for fear of his excommunication: and such as receive Orders from him do not receive the exercise of their Orders, even though they are ignorant of his being guilty of simony; and they need to receive a dispensation. Some, however, maintain that one ought to receive Orders in obedience to his command unless one can prove him to be guilty of simony, but that one ought not to exercise the Order without a dispensation. But this is an unreasonable statement, because no one should obey a man to the extent of communicating with him in an unlawful action. Now he that is, by virtue of the law, suspended as regards both himself and others, confers Orders unlawfully: wherefore no one should communicate with him, by receiving Orders from him for any cause whatever. If, however, one be not certain on the point, one ought not to give credence to another's sin, and so one ought with a good conscience to receive Orders from him. And if the bishop has been guilty of simony otherwise than by a simoniacal promotion, and the fact be a secret, one can receive Orders from him because he is not suspended as regards others, but only as regards himself, as stated above (ad 1).
3. To be deprived of what one has received is not only the punishment of a sin, but is also sometimes the effect of acquiring unjustly, as when one buys a thing of a person who cannot sell it. Wherefore if a man, knowingly and spontaneously, receives Orders or an ecclesiastical benefice simoniacally, not only is he deprived of what he has received, by forfeiting the exercise of his order, and resigning the benefice and the fruits acquired therefrom, but also in addition to this he is punished by being marked with infamy. Moreover, he is bound to restore not only the fruit actually acquired, but also such as could have been acquired by a careful possessor (which, however, is to be understood of the net fruits, allowance being made for expenses incurred on account of the fruits), excepting those fruits that have been expended for the good of the Church.On the other hand, if a man's promotion be procured simoniacally by others, without his knowledge and consent, he forfeits the exercise of his Order, and is bound to resign the benefice obtained together with fruits still extant; but he is not bound to restore the fruits which he has consumed, since he possessed them in good faith. Exception must be made in the case when his promotion has been deceitfully procured by an enemy of his; or when he expressly opposes the transaction, for then he is not bound to resign, unless subsequently he agree to the transaction, by paying what was promised.
4. Money, property, or fruits simoniacally received, must be restored to the Church that has incurred loss by their transfer, notwithstanding the fact that the prelate or a member of the chapter of that church was at fault, since others ought not to be the losers by his sin: in suchwise, however, that, as far as possible, the guilty parties be not the gainers. But if the prelate and the entire chapter be at fault, restitution must be made, with the consent of superior authority, either to the poor or to some other church.
5. If there are any persons who have been simoniacally admitted into a monastery, they must quit: and if the simony was committed with their knowledge since the holding of the General Council [*Fourth Lateran Council, A.D. 1215, held by Innocent III], they must be expelled from their monastery without hope of return, and do perpetual penance under a stricter rule, or in some house of the same order, if a stricter one be not found. If, however, this took place before the Council, they must be placed in other houses of the same order. If this cannot be done, they must be received into monasteries of the same order, by way of compensation, lest they wander about the world, but they must not be admitted to their former rank, and must be assigned a lower place.On the other hand, if they were received simoniacally, without their knowledge, whether before or after the Council, then after quitting they may be received again, their rank being changed as stated.
6. In God's sight the mere will makes a man guilty of simony; but as regards the external ecclesiastical punishment he is not punished as a simoniac, by being obliged to resign, but is bound to repent of his evil intention.
7. The Pope alone can grant a dispensation to one who has knowingly received a benefice (simoniacally). In other cases the bishop also can dispense, provided the beneficiary first of all renounce what he has received simoniacally, so that he will receive either the lesser dispensation allowing him to communicate with the laity, or a greater dispensation, allowing him after doing penance to retain his order in some other Church; or again a greater dispensation, allowing him to remain in the same Church, but in minor orders; or a full dispensation allowing him to exercise even the major orders in the same Church, but not to accept a prelacy.


After religion we must consider piety, the consideration of which will render the opposite vices manifest. Accordingly four points of inquiry arise with regard to piety:

(1) To whom does piety extend?

(2) What does piety make one offer a person?

(3) Whether piety is a special virtue?

(4) Whether the duties of piety should be omitted for the sake of religion?

Whether piety extends to particular human individuals?

Objection: 1. It seems that piety does not extend to particular human individuals. For Augustine says (De Civ. Dei x) that piety denotes, properly speaking, the worship of God, which the Greeks designate by the term (eusebeia). But the worship of God does not denote relation to man, but only to God. Therefore piety does not extend definitely to certain human individuals.
2. Further, Gregory says (Moral. i): "Piety, on her day, provides a banquet, because she fills the inmost recesses of the heart with works of mercy." Now the works of mercy are to be done to all, according to Augustine (De Doctr. Christ. i). Therefore piety does not extend definitely to certain special persons.
3. Further, in human affairs there are many other mutual relations besides those of kindred and citizenship, as the Philosopher states (Ethic. viii, 11,12), and on each of them is founded a kind of friendship, which would seem to be the virtue of piety, according to a gloss on 2Tm 3,5, "Having an appearance indeed of piety [Douay: 'godliness']." Therefore piety extends not only to one's kindred and fellow-citizens.

On the contrary Tully says (De Invent. Rhet. ii) that "it is by piety that we do our duty towards our kindred and well-wishers of our country and render them faithful service."
I answer that Man becomes a debtor to other men in various ways, according to their various excellence and the various benefits received from them. on both counts God holds first place, for He is supremely excellent, and is for us the first principle of being and government. In the second place, the principles of our being and government are our parents and our country, that have given us birth and nourishment. Consequently man is debtor chiefly to his parents and his country, after God. Wherefore just as it belongs to religion to give worship to God, so does it belong to piety, in the second place, to give worship to one's parents and one's country.The worship due to our parents includes the worship given to all our kindred, since our kinsfolk are those who descend from the same parents, according to the Philosopher (Ethic. viii, 12). The worship given to our country includes homage to all our fellow-citizens and to all the friends of our country. Therefore piety extends chiefly to these.

Reply to Objection: 1. The greater includes the lesser: wherefore the worship due to God includes the worship due to our parents as a particular. Hence it is written (Ml 1,6): "If I be a father, where is My honor?" Consequently the term piety extends also to the divine worship.
2. As Augustine says (De Civ. Dei x), "the term piety is often used in connection with works of mercy, in the language of the common people; the reason for which I consider to be the fact that God Himself has declared that these works are more pleasing to Him than sacrifices. This custom has led to the application of the word 'pious' to God Himself."
3. The relations of a man with his kindred and fellow-citizens are more referable to the principles of his being than other relations: wherefore the term piety is more applicable to them.

Whether piety provides support for our parents?

Objection: 1. It seems that piety does not provide support for our parents. For, seemingly, the precept of the decalogue, "Honor thy father and mother," belongs to piety. But this prescribes only the giving of honor. Therefore it does not belong to piety to provide support for one's parents.
2. Further, a man is bound to lay up for those whom he is bound to support. Now according to the Apostle (2Co 12,14), "neither ought the children to lay up for the parents." Therefore piety does not oblige them to support their parents.
3. Further, piety extends not only to one's parents, but also to other kinsmen and to one's fellow-citizens, as stated above (Article [1]). But one is not bound to support all one's kindred and fellow-citizens. Therefore neither is one bound to support one's parents.

On the contrary our Lord (Mt 15,3-6) reproved the Pharisees for hindering children from supporting their parents.
I answer that We owe something to our parents in two ways: that is to say, both essentially, and accidentally. We owe them essentially that which is due to a father as such: and since he is his son's superior through being the principle of his being, the latter owes him reverence and service. Accidentally, that is due to a father, which it befits him to receive in respect of something accidental to him, for instance, if he be ill, it is fitting that his children should visit him and see to his cure; if he be poor, it is fitting that they should support him; and so on in like instance, all of which come under the head of service due. Hence Tully says (De Invent. Rhet. ii) that "piety gives both duty and homage": "duty" referring to service, and "homage" to reverence or honor, because, as Augustine says (De Civ. Dei x), "we are said to give homage to those whose memory or presence we honor."

Reply to Objection: 1. According to our Lord's interpretation (Mt 15,3-6) the honor due to our parents includes whatever support we owe them; and the reason for this is that support is given to one's father because it is due to him as to one greater.
2. Since a father stands in the relation of principle, and his son in the relation of that which is from a principle, it is essentially fitting for a father to support his son: and consequently he is bound to support him not only for a time, but for all his life, and this is to lay by. On the other hand, for the son to bestow something on his father is accidental, arising from some momentary necessity, wherein he is bound to support him, but not to lay by as for a long time beforehand, because naturally parents are not the successors of their children, but children of their parents.
3. As Tully says (De Invent. Rhet. ii), "we offer homage and duty to all our kindred and to the well-wishers of our country"; not, however, equally to all, but chiefly to our parents, and to others according to our means and their personal claims.

Whether piety is a special virtue distinct from other virtues?

Objection: 1. It seems that piety is not a special virtue distinct from other virtues. For the giving of service and homage to anyone proceeds from love. But it belongs to piety. Therefore piety is not a distinct virtue from charity.
2. Further, it is proper to religion to give worship to God. But piety also gives worship to God, according to Augustine (De Civ. Dei x). Therefore piety is not distinct from religion.
3. Further, piety, whereby we give our country worship and duty, seems to be the same as legal justice, which looks to the common good. But legal justice is a general virtue, according to the Philosopher (Ethic. v, 1,2). Therefore piety is not a special virtue.

On the contrary It is accounted by Tully (De Invent. Rhet. ii) as a part of justice.
I answer that A special virtue is one that regards an object under a special aspect. Since, then, the nature of justice consists in rendering another person his due, wherever there is a special aspect of something due to a person, there is a special virtue. Now a thing is indebted in a special way to that which is its connatural principle of being and government. And piety regards this principle, inasmuch as it pays duty and homage to our parents and country, and to those who are related thereto. Therefore piety is a special virtue.

Reply to Objection: 1. Just as religion is a protestation of faith, hope and charity, whereby man is primarily directed to God, so again piety is a protestation of the charity we bear towards our parents and country.
2. God is the principle of our being and government in a far more excellent manner than one's father or country. Hence religion, which gives worship to God, is a distinct virtue from piety, which pays homage to our parents and country. But things relating to creatures are transferred to God as the summit of excellence and causality, as Dionysius says (Div. Nom. i): wherefore, by way of excellence, piety designates the worship of God, even as God, by way of excellence, is called "Our Father."
3. Piety extends to our country in so far as the latter is for us a principle of being: but legal justice regards the good of our country, considered as the common good: wherefore legal justice has more of the character of a general virtue than piety has.

Whether the duties of piety towards one's parents should be omitted for the sake of religion?

Objection: 1. It seems that the duties of piety towards one's parents should be omitted for the sake of religion. For Our Lord said (Lc 14,26): "If any man come to Me, and hate not his father, and mother, and wife, and children, and brethren, and sisters, yea and his own life also, he cannot be My disciple." Hence it is said in praise of James and John (Mt 4,22) that they left "their nets and father, and followed" Christ. Again it is said in praise of the Levites (Dt 33,9): "Who hath said to his father, and to his mother: I do not know you; and to his brethren: I know you not; and their own children they have not known. These have kept Thy word." Now a man who knows not his parents and other kinsmen, or who even hates them, must needs omit the duties of piety. Therefore the duties of piety should be omitted for the sake of religion.
2. Further, it is written (Lc 9,59-60) that in answer to him who said: "Suffer me first to go and bury my father," Our Lord replied: "Let the dead bury their dead: but go thou, and preach the kingdom of God." Now the latter pertains to religion, while it is a duty of piety to bury one's father. Therefore a duty of piety should be omitted for the sake of religion.
3. Further, God is called "Our Father" by excellence. Now just as we worship our parents by paying them the duties of piety so do we worship God by religion. Therefore the duties of piety should be omitted for the sake of the worship of religion.
4. Further, religious are bound by a vow which they may not break to fulfil the observances of religion. Now in accordance with those observances they are hindered from supporting their parents, both on the score of poverty, since they have nothing of their own, and on the score of obedience, since they may not leave the cloister without the permission of their superior. Therefore the duties of piety towards one's parents should be omitted for the sake of religion.

On the contrary Our Lord reproved the Pharisees (Mt 15,3-6) who taught that for the sake of religion one ought to refrain from paying one's parents the honor we owe them.
I answer that Religion and piety are two virtues. Now no virtue is opposed to another virtue, since according to the Philosopher, in his book on the Categories (Cap. De oppos.), "good is not opposed to good." Therefore it is impossible that religion and piety mutually hinder one another, so that the act of one be excluded by the act of the other. Now, as stated above (FS, Question [7], Article [2]; FS, Question [18], Article [3]), the act of every virtue is limited by the circumstances due thereto, and if it overstep them it will be an act no longer of virtue but of vice. Hence it belongs to piety to pay duty and homage to one's parents according to the due mode. But it is not the due mode that man should tend to worship his father rather than God, but, as Ambrose says on Lc 12,52, "the piety of divine religion takes precedence of the claims of kindred."Accordingly, if the worship of one's parents take one away from the worship of God it would no longer be an act of piety to pay worship to one's parents to the prejudice of God. Hence Jerome says (Ep ad Heliod.): "Though thou trample upon thy father, though thou spurn thy mother, turn not aside, but with dry eyes hasten to the standard of the cross; it is the highest degree of piety to be cruel in this matter." Therefore in such a case the duties of piety towards one's parents should be omitted for the sake of the worship religion gives to God. If, however, by paying the services due to our parents, we are not withdrawn from the service of God, then will it be an act of piety, and there will be no need to set piety aside for the sake of religion.

Reply to Objection: 1. Gregory expounding this saying of our Lord says (Hom. xxxvii in ) that "when we find our parents to be a hindrance in our way to God, we must ignore them by hating and fleeing from them." For if our parents incite us to sin, and withdraw us from the service of God, we must, as regards this point, abandon and hate them. It is in this sense that the Levites are said to have not known their kindred, because they obeyed the Lord's command, and spared not the idolaters (Ex 32). James and John are praised for leaving their parents and following our Lord, not that their father incited them to evil, but because they deemed it possible for him to find another means of livelihood, if they followed Christ.
2. Our Lord forbade the disciple to bury his father because, according to Chrysostom (Hom. xxviii in Matth.), "Our Lord by so doing saved him from many evils, such as the sorrows and worries and other things that one anticipates under these circumstances. For after the burial the will had to be read, the estate had to be divided, and so forth: but chiefly, because there were others who could see to the funeral." Or, according to Cyril's commentary on Lc 9, "this disciple's request was, not that he might bury a dead father, but that he might support a yet living father in the latter's old age, until at length he should bury him. This is what Our Lord did not grant, because there were others, bound by the duties of kindred, to take care of him."
3. Whatever we give our parents out of piety is referred by us to God; just as other works of mercy which we perform with regard to any of our neighbors are offered to God, according to Mt 25,40: "As long as you did it to one of . . . My least . . . you did it to Me." Accordingly, if our carnal parents stand in need of our assistance, so that they have no other means of support, provided they incite us to nothing against God, we must not abandon them for the sake of religion. But if we cannot devote ourselves to their service without sin, or if they can be supported without our assistance, it is lawful to forego their service, so as to give more time to religion.
4. We must speak differently of one who is yet in the world, and of one who has made his profession in religion. For he that is in the world, if he has parents unable to find support without him, he must not leave them and enter religion, because he would be breaking the commandment prescribing the honoring of parents. Some say, however, that even then he might abandon them, and leave them in God's care. But this, considered aright, would be to tempt God: since, while having human means at hand, he would be exposing his parents to danger, in the hope of God's assistance. on the other hand, if the parents can find means of livelihood without him, it is lawful for him to abandon them and enter religion, because children are not bound to support their parents except in cases of necessity, as stated above. He that has already made his profession in religion is deemed to be already dead to the world: wherefore he ought not, under pretext of supporting his parents, to leave the cloister where he is buried with Christ, and busy himself once more with worldly affairs. Nevertheless he is bound, saving his obedience to his superiors, and his religious state withal, to make points efforts for his parents' support.

Summa Th. II-II EN Qu.100 a.4