Christian unity in Jesus Christ is supremely important, but so also is doctrinal agreement across the board.
Catholics certainly recognize Protestants as fellow Christians, who have (according to the Council of Trent) been validly baptized (provided only that it was trinitarian). Holy Communion is a somewhat different matter. That is a symbol of unity (doctrinal and relational), and such oneness is currently lacking in the Body of Christ.
For us to offer Communion to anyone without requiring doctrinal consent would be dishonest for us and in our opinion a corruption of Communion as a symbol of unity in the Body.
It’s not a matter of “looking down” upon our “separated brethren” but of simple honesty and seeking to be true to what we feel is Christ’s teaching.
Christian unity in Jesus Christ is supremely important, but so also is doctrinal agreement across the board, according to Paul’s statement: “. . . one Lord, one faith, one baptism” (Ephesians 4:5) and many passages that refer to a common “faith” (i.e., a communal profession of a particular, identifiable set of doctrines):
Acts 6:7 (RSV) . . . a great many of the priests were obedient to the faith.
Galatians 1:23 . . . He . . . is now preaching the faith he once tried to destroy.
1 Timothy 1:2 To Timothy, my true child in the faith . . .
1 Timothy 3:9 they must hold the mystery of the faith with a clear conscience.
1 Timothy 4:1 . . . some will depart from the faith by giving heed to deceitful spirits and doctrines of demons.
1 Timothy 4:6 . . . nourished on the words of the faith and of the good doctrine which you have followed.
Titus 1:4 To Titus, my true child in a common faith . . .
Jude 3 . . . contend for the faith which was once for all delivered to the saints.
Now, if a person wants to argue that this doesn’t apply to the Eucharist, Catholics must disagree (with all due respect) again, because Paul is very clear in 1 Corinthians 10:16 and 11:27-30 that he regards the Eucharist as the literal Body and Blood of Christ.
Moreover, in the context of the eucharistic Pauline passages, we also see his concern for doctrinal and familial unity in the Body of Christ. Six verses before one of these passages Paul writes:
1 Corinthians 11:17-19 But in the following instructions I do not commend you, because when you come together it is not for the better but for the worse. For, in the first place, when you assemble as a church, I hear that there are divisions among you; and I partly believe it, for there must be factions among you in order that those who are genuine among you may be recognized.
Fifteen verses before this passage, Paul mentioned apostolic traditions:
1 Corinthians 11:2 I commend you because you remember me in everything and maintain the traditions even as I have delivered them to you.
And in the very next verse after his strong statement of the Real Presence, Paul talks about unity also:
1 Corinthians 10:16-17 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.
1 Corinthians 11:2 above occurs 17 verses after this passage. It is all of a piece: doctrinal unity, unity in love, and partaking of the Eucharist. The Catholic view, then, as we see, is eminently biblical: there is one faith, and the Eucharist, as a symbol of this doctrinal unity, is the actual Body and Blood. That is the received faith. If someone doesn’t believe this, they shouldn’t partake of the Eucharist, because it is the central rite of the Christian faith.
I continue to be baffled as to why this is such an issue for many Protestants. It never was for me before I converted. I never felt excluded because I was not yet a Catholic in belief.
All Christian groups believe certain things. And when one thing is believed, logic dictates that its contraries are excluded and regarded as false. It doesn’t follow that it is prideful to do so. Closed Communion is not a denial of mercy at all, but simply a requirement for inclusion into the community, as St. Paul taught us.
It was always the case that the new Catholic had to undergo a lengthy period of catechesis and introduction to the Catholic ethos before being admitted to the Lord’s Table. We can’t simply change that because some Protestants are distraught over it.
Some people can’t meet the requirements to get into the military. A seven-foot man is not likely to be a jockey, and a five-foot man will likely not get into the NBA (though a few actually have). One has to meet requirements to enter a college or to be hired at a job. You have to be 35 to be President of the United States, and 30 to be a Senator. Should the Harvard Law School bend its rules just so I can admitted?
Likewise, being a Catholic means something intellectually; doctrinally. Many denominations care little about doctrinal distinctives, but we Catholics do, and so did all the early Protestants (and, I would say, Jesus and the apostles and Church fathers). We presuppose a doctrinal unity. Receiving Communion is being part of the Catholic Church. Therefore, one who doesn’t agree with Catholic teachings cannot partake.
This is not solely a “Catholic matter” when all is said and done, but a question of every Christian group’s prerogative to set its own rules of entrance and participation. To be a member of a Christian group is (by definition and essence) to believe certain things: to give assent to them. And these include practice and questions of who receives Holy Communion and when, and after how much preparation.