Excommunication is the Church’s most severe penalty imposed for particularly grave sins. Through baptism, a person is incorporated into the body of the Church through which there is a “communication” of spiritual goods. By committing a particularly grave sin and engaging in activities which cause grave scandal and fracture the body of the Church, that communication ceases, and the person is deprived of receiving the sacraments and other privileges.
The practice of excommunication arose in the early Church. In his First Letter to the Corinthians, St. Paul castigated that community for tolerating the practice of incest– “a man living with his father’s wife” (I Corinthians 5:1). He admonished the Corinthians for not removing the offender from their midst. St. Paul said, “I hand him over to Satan for the destruction of his flesh, so that his spirit may be saved on the day of the Lord” (5:5). St. Paul further warned against associating with anyone who bears the title “brother” (indicating being a believer and part of the Church) but who is immoral, covetous, an idolater, an abusive person, a drunkard, or a thief. He then closed the passage by quoting from the Torah, “Expel the wicked man from your midst” (Deuteronomy 6:13).
Note, however, that St. Paul also expressed hope. He imposed the sanction upon the offender “so that his spirit may be saved on the day of the Lord,” indicating a hope for repentance, conversion, and a readmittance into the community. (This motive is affirmed also in II Thessalonians 3:15 and II Corinthians 2:5-11.) Nevertheless, until such time, the obstinate sinner had to be removed to prevent both the infection of the rest of the believers and the appearance of condoning such a sinful action.
Later, excommunication became clearly associated with the Sacrament of Penance. At this time, the Sacrament of Penance was generally received once. Seeking forgiveness, serious sinners presented themselves to the bishop, who assigned them to a class of penitents (ordo paenitentium). The penitents were liturgically excommunicated from the Church and assigned to perform a penance, which usually lasted weeks, even months. Once the penance was completed, the bishop formally lifted the excommunication, absolved the sinners, and welcomed them back into full communion with the Church. By the seventh century, the Sacrament of Penance was repeatable and became more as we know it today, while the idea of excommunication became a severe Church penalty imposed for only the most serious offenses. Nevertheless, the lifting of the penalty of excommunication still was linked with the making of a good sacramental confession and the reception of absolution.
The Code of Canon Law (1983) specifies that an excommunicated person is forbidden to participate in a ministerial capacity (celebrant, lector, etc.) in the Sacrifice of the Mass or in any other form of public worship; to celebrate or to receive the sacraments; to celebrate the sacramentals; to exercise any ecclesiastical office or ministry; and to issue any act of governance (#1331.1). An excommunicated person also cannot be received into a public association of the Christian faithful (#316.1).
On one hand, the penalty of excommunication can be imposed by a proper authority (ferendae sententiae) or incurred automatically (latae sententiae). A bishop may directly impose the penalty of excommunication, but only for the most serious offenses and after giving due warning (#1318). Following the same rationale of the early Church, this severe penalty intends to correct the individual and to foster better church discipline (#1317). As the shepherd of his diocese, a bishop must protect both the souls of the faithful from the infection of error and sin, and of those who are jeopardizing their salvation. The bishop or his delegate may remit the penalty when the sinner has repented and has sought reconciliation.
On the other hand, a person can also incur automatic excommunication. A person who is an apostate from the faith, a heretic, or a schismatic (#1364); or one who procures a successful abortion (#1398) is automatically excommunicated. In these cases, the local ordinary or a delegated priest can remit the penalty.
In some very grievous cases, only the Holy See can lift the ban of an automatic excommunication: if a person desecrates the Blessed Sacrament or uses it for a sacrilegious purpose (#1367); if a person uses physical force against the Pope (#1370); if a priest absolves an accomplice in a sin against the Sixth Commandment (#1378); if a bishop consecrates someone as a bishop without permission of the Holy Father (#1982); and if a priest directly violates the seal of confession (#1388).
We must keep in mind that the purpose of excommunication is to shock the sinner into repentance and conversion. Excommunication is a powerful way of making a person realize his immortal soul is in jeopardy. Excommunication does not “lock the door” of the Church to the person forever, but hopes to bring the person back into communion with the whole Church. Moreover, this penalty awakens all of the faithful to the severity of these sins and deters them from the commission of these sins. This line of thought is highlighted in the Catechism when it speaks of the automatic excommunication for abortion: “The Church does not thereby intend to restrict the scope of mercy. Rather, she makes clear the gravity of the crime committed, the irreparable harm done to the innocent who is put to death, as well as to the parents and the whole of society” (#2272). In all, while the Church imposes this severe penalty for just cause, she also remembers, “A heart contrite and humbled, O God, you will not spurn” (Psalm 51:19).