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.
Objection 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.
Objection 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 (I-II, 74, 1 and 2; I-II, 77, 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.
Objection 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.
Objection 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.
Objection 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 (1, ad 2). Therefore a person should not always be deprived of what he has acquired by simony.
Objection 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 Matthew 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.
Reply to Objection 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).
Reply to Objection 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.
Reply to Objection 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.
Reply to Objection 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, 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.
Reply to Objection 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.
Reply to Objection 7. The Pope alone can grant a dispensation to one who has knowingly received a benefice (simoniacally). On 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.
Source: Summa Theologica (New Advent)