COMMUNICATION IN SACRED MATTERS. — By these terms is understood the participation of Catholics in the sacred ceremonies (prayers, services, sermons, rites) performed by non-Catholics (heretics, schismatics, infidels) inside or outside their churches or temples. This participation may be: active, that is, when one takes part positively in religious worship, performing some act related to it; passive, when one takes part only negatively, abstaining from every action connected with the religious ceremony; formal, when there is the adherence of mind and heart; material, when this adherence is absent and everything is reduced to an act of external and physical presence. C. in s. m. is usually designated by the name c. in divinis, to distinguish it from c. in profanis, that is, in private and public relations concerning domestic and civil life, and from c. in rebus mixtis, that is, in relations involving acts that may be considered religious or that also have a religious aspect, such as marriages, funerals, and similar ceremonies.
The conduct of Catholics in this regard is regulated in general by the CIC, and in its various applications by the norms issued by the Roman S. Congregations.
I. C. in profanis. — According to the law currently in force, it is licit when there is no danger of spiritual harm; illicit when such danger exists. Therefore, even those actions must be avoided which, especially in certain specific circumstances, may signify or entail excessive and consequently dangerous familiarity, confidence, or intimacy with non-Catholics, especially for persons «simple and weak in faith» (cf. Sum. Theol., 2a-2ae, q. 10, a. 9). Relations with excommunicated persons who are to be avoided are regulated by particular norms (CIC, can. 2267).
II. C. in divinis. — It is never licit for the faithful to attend actively or to take part in any way in the sacred rites of non-Catholics (CIC, can. 1258 § 1). This applies not only when the rites in question are false or impious in themselves, but also when they are rites proper to this or that heretical, schismatic, or pagan sect or group. For such participation is equivalent to the profession of a false religion and consequently to the denial of the Catholic faith. And even if every idea of denial could be excluded, three very serious harms would always remain: 1) the danger of perversion in the Catholic who takes part; 2) scandal, both among the faithful, who are given cause to judge ill of the person dealing with the opponents of the faith and perhaps even to doubt its truth, and among non-Catholics themselves, who are thereby confirmed in their error; 3) indifferentism in religious matters, that is, the outward approval of erroneous beliefs and the idea that the external expression of one’s faith is a negligible matter.
In particular: 1. Sacraments: a) Baptism: a Catholic may not act as sponsor, even through an intermediary, at a Baptism conferred by a heretical minister, because this would be tantamount to undertaking to instruct, or to have the baptized person instructed, in an erroneous doctrine (S. Uffizio, 10 May 1710; 7 July 1864; Collectan. de Prop. Fide, Roma 1907, nn. 478, 1257). b) Eucharist: a Catholic may not attend the Mass of a heretical or schismatic priest, even if, should the Sunday obligation be pressing, he would otherwise have to remain without Mass (S. Uffizio, 7 Aug. 1704; ibid., n. 267). c) Marriage: it is not licit to contract marriage before a heterodox minister, not even in the case of a mixed-religion marriage, nor even if one has already contracted, or intends afterward to contract, it before a Catholic priest (CIC, can. 1065). The transgression entails excommunication reserved to the Ordinary (can. 2319). If, however, the heterodox minister acts only as a State official, it is licit to make use of him when this entails no danger of perversion or scandal or of contempt for ecclesiastical authority (can. 1526 § 2). d) Last Sacraments: in danger of death, if a Catholic priest is unavailable, absolution may be received from a heretical priest, on condition that there is a probability that it will be given according to the Catholic rite (S. Uffizio, 30 June and 7 July 1864; Collectan. de Propag. Fide, n. 1257, ad 6). Moreover, a Catholic may not call a minister of a heterodox religion to the bedside of a dying person of the same religion in order that he may administer the Sacraments. He may, however, seek the intervention of a member of the sick person’s religion, or even himself inform the heterodox minister simply of the dying person’s desire to receive a visit from him. In this second case, there is nothing more than an invitation such as one would address to any person, relative or friend. — 2. Other ceremonies. Catholics are forbidden to pray, sing, or play the organ in the churches and chapels of heretics and schismatics, either alone or with them, while they are conducting their religious services (S. Congr. di Propag. Fide, 12 June and 8 July 1889; Collectan. de Prop. Fide, n. 1713). — 3. Public disputes. Catholics may not take part in discussions and controversies, especially public ones, on matters of faith with non-Catholics without the permission of the Holy See or, in urgent cases, of the Ordinary (CIC, can. 1325 § 3). — 4. Common use of a church. The Ordinary may grant the use of a Catholic church for the services of dissenters, though at times different from those of the Catholic services. This occurs, for example, in Abazia, Germany, Switzerland, and in the church of the Holy Sepulchre in Jerusalem (S. Uffizio, 5 June 1889; CIC, Fontes, n. 1119).
III. C. in rebus mixtis. — Purely passive presence or participation in the ceremonies of a non-Catholic religion is tolerated by the Church when there is a motive of honor or civil respect; on condition, however, that the motive be serious (approved, in case of doubt, by the Ordinary), that the danger of scandal or perversion be excluded, and that no part be taken in them, either immediately or mediately. Thus, in these cases, one may attend the funerals, marriages, and other similar ceremonies of non-Catholics (CIC, can. 1258 § 2).
Thus, in the case of funerals: a) if the funeral is organized as a manifestation of unbelief or contempt for the Catholic religion, one may not participate in it (S. Uffizio, 11 May 1892; CIC, Fontes, n. 1154); b) in other cases one may do so either out of a sense of civil duty (when, for example, the deceased is one’s employer, a military commander, or the head of State), or for reasons of honor (when the deceased is a close relative, a public benefactor, or a very intimate friend). In accompanying the funeral procession, however, one may not carry a lighted candle, offer suffrages for the soul of the deceased, or sing, because these and similar acts indicate participation in the religious rite. Visiting the churches of heretics may be permitted out of curiosity or for purposes of study, provided that it entails no intention whatsoever of participating in any religious rites that may take place there and is not imposed by the civil authority in order to indicate a harmony of beliefs between Catholics and non-Catholics (S. Uffizio, 13 Jan. 1818; CIC, Fontes, n. 856).