Summa Theologica Suppl, q. 23: Of Communication with Excommunicated Persons
Article 2. Whether a person incurs excommunication for communicating with one who is excommunicated?
Objection 1It would seem that a person does not incur excommunication for communicating with one who is excommunicated. For a heathen or a Jew is more separated from the Church than a person who is excommunicated. But one does not incur excommunication for communicating with a heathen or a Jew. Neither, therefore, does one for communicating with an excommunicated Christian.
Objection 2Further, if a man incurs excommunication for communicating with an excommunicated person, for the same reason a third would incur excommunication for communicating with him, and thus one might go on indefinitely, which would seem absurd. Therefore one does not incur excommunication for communicating with one who is excommunicated.
On the contraryAn excommunicated person is banished from communion. Therefore whoever communicates with him leaves the communion of the Church: and hence he seems to be excommunicated.
I answer thatA person may incur excommunication in two ways. First, so that the excommunication includes both himself and whosoever communicates with him: and then, without any doubt, whoever communicates with him, incurs a major excommunication. Secondly, so that the excommunication is simply pronounced on him; and then a man may communicate with him either in his crime, by counsel, help or favor, in which case again he incurs the major excommunication, or he may communicate with him in other things by speaking to him, greeting him, or eating with him, in which case he incurs the minor excommunication.
Reply to Objection 1The Church has no intention of correcting unbelievers as well as the faithful who are under her care: hence she does not sever those, whom she excommunicates, from the fellowship of unbelievers, as she does from the communion of the faithful over whom she exercises a certain power.
Reply to Objection 2It is lawful to hold communion with one who has incurred a minor excommunication, so that excommunication does not pass on to a third person.
Article 3. Whether it is always a mortal sin to communicate with an excommunicated person in other cases than those in which it is allowed?
Objection 1It would seem that it is always a mortal sin to hold communion with an excommunicated person in other cases than those in which it is allowed. Because a certain decretal (Cap. Sacris: De his quae vi, metuve, etc.) declares that "not even through fear of death should anyone hold communion with an excommunicated person, since one ought to die rather than commit a mortal sin." But this would be no reason unless it were always a mortal sin to hold communion with an excommunicated person. Therefore, etc.
Objection 2Further, it is a mortal sin to act against a commandment of the Church. But the Church forbids anyone to hold communion with an excommunicated person. Therefore it is a mortal sin to hold communion with one who is excommunicated.
Objection 3Further, no man is debarred from receiving the Eucharist on account of a venial sin. But a man who holds communion with an excommunicated person, outside those cases in which it is allowed, is debarred from receiving the Eucharist, since he incurs a minor excommunication. Therefore it is a mortal sin to hold communion with an excommunicated person, save in those cases in which it is allowed.
Objection 4Further, no one should incur a major excommunication save for a mortal sin. Now according to the law (Can. Praecipue, seqq., caus. xi) a man may incur a major excommunication for holding communion with an excommunicated person. Therefore it is a mortal sin to hold communion with one who is excommunicated.
On the contraryNone can absolve a man from mortal sin unless he have jurisdiction over him. But any priest can absolve a man for holding communion with those who are excommunicated. Therefore it is not a mortal sin.
Further, the measure of the penalty should be according to the measure of the sin, as stated in Dt. 25:3. Now the punishment appointed by common custom for holding communion with an excommunicated person is not that which is inflicted for mortal sin, but rather that which is due for venial sin. Therefore it is not a mortal sin.
I answer thatSome hold that it is always a mortal sin to hold communion with an excommunicated person, by word or in any of the forbidden ways mentioned above (A[2]), except in those cases allowed by law (Cap. Quoniam). But since it seems very hard that a man should be guilty of a mortal sin by uttering just a slight word to an excommunicated person, and that by excommunicating a person one would endanger the salvation of many, and lay a snare which might turn to one's own hurt, it seems to others more probable that he is not always guilty of a mortal sin, but only when he holds communion with him in a criminal deed, or in an act of Divine worship, or through contempt of the Church.
Reply to Objection 1This decretal is speaking of holding communion in Divine worship. It may also be replied that the same reason applies both to mortal and venial sin, since just as one cannot do well by committing a mortal sin, so neither can one by committing a venial sin: so that just as it is a man's duty to suffer death rather than commit a mortal sin, so is it his duty to do so sooner than commit a venial sin, inasmuch as it is his duty to avoid venial sin.
Reply to Objection 2The commandment of the Church regards spiritual matters directly, and legitimate actions as a consequence: hence by holding communion in Divine worship one acts against the commandment, and commits a mortal sin; but by holding communion in other matters, one acts beside the commandment, and sins venially.
Reply to Objection 3Sometimes a man is debarred from the Eucharist even without his own fault, as in the case of those who are suspended or under an interdict, because these penalties are sometimes inflicted on one person for the sin of another who is thus punished.
Reply to Objection 4Although it is a venial sin to hold communion with one who is excommunicated, yet to do so obstinately is a mortal sin: and for this reason one may be excommunicated according to the law.