Day 192: Unity in the Eucharist

The unity of the Mystical Body: the Eucharist makes the Church. Those who receive the Eucharist are united more closely to Christ. Through it, Christ unites them to all the faithful in one body - the Church. Communion renews, strengthens, and deepens this incorporation into the Church, already achieved by Baptism. In Baptism we have been called to form but one body. The Eucharist fulfills this call: "The cup of blessing which we bless, is it not a participation in the blood of Christ? The bread which we break, is it not a participation in the body of Christ? Because there is one bread, we who are many are one body, for we all partake of the one bread:" CCC 1396

In today's reading, the Catechism speaks of the unity in the Eucharist. By receiving it, we are "united more closely to Christ" and with others of the faithful in the Church. While  Christ prayed for and desires our unity (Jn 17:21), we also must take into consideration St. Paul's warning not to partake of the Eucharist in an "unworthy manner" (1 Cor 11:27). The Catechism Companion, Vol II comments on this for Catholics:

The conditions for receiving Holy Communion include Baptism, faith in Jesus as Lord, and unity with one's bishop. Catholics who are not in full communion with the Church, due to mortal sin or other irregularities, should not receive Holy Communion. (p. 148)

These "conditions" also apply to some degree to our separated Eastern Orthodox and Protestant brethren. The former are recognized by the Church as "joined to us in closest intimacy" despite not being in full communion due in part to their "celebrat[ing] the Eucharist with great love,"  that they "possess true sacraments," have apostolic succession, and therefore reception of the Eucharist "given suitable circumstances and the approval of Church authority, is not merely possible but is encouraged" (CCC 1399). They are designated as "Eastern churches" because of all this and not "ecclesial communities" despite our separation from each other, unlike Christians "derived from the Reformation and separated from the Catholic Church".

For Protestants, the situation is different. Because they "have not preserved the proper reality of the Eucharistic mystery in its fullness, especially because of the absence of the sacrament of Holy Orders" the Church teaches that "Eucharistic intercommunion with these communities is not possible" (CCC 1400). 

The Catechism Compendium summarizes Church teaching on the reception of the Eucharist by individual non-Catholic Christians:

Catholic ministers may give Holy Communion licitly to members of the Oriental Churches which are not in full communion with the Catholic Church whenever they ask for it of their own will and possess the required dispositions. Catholic ministers may licitly give Holy Communion to members of other ecclesial communities only if, in grave necessity, they ask for it of their own will, possess the required dispositions, and give evidence of holding the Catholic faith regarding the sacrament. (#293)