Reformed writer Peter Leithhart argues against the closed communion practices of Catholics, Orthodox, and Lutherans on the basis of Galatians 2:
The battle between Paul and the Judaizers focused on table fellowship. Initially, Peter didn’t require Gentiles to “judaize” but ate openly with uncircumcised Gentiles. Pressured by believers from the Jerusalem church, though, he withdrew and refused to share meals with Gentiles anymore. Whether these were common or sacred meals, the same logic would apply to both: If Peter wouldn’t eat common meals with unclean Gentiles, he certainly would have avoided the contagion of Gentiles at sacred meals. For Paul, this wasn’t a small or marginal issue. In Paul’s judgment, Peter was “not straightforward about the gospel” and his actions undermined justification by faith. Unless Jews and Gentiles share a common table, Paul insisted, the Gospel is compromised. . .
For Paul, Christians should share meals with any and all who confess faith in Jesus, whether Jew or Greek, slave or free, male or female, and this unity should be especially evident in the Eucharistic meal that is the high point of Christian liturgy. One Lord must have one people sitting at one table. Any additional requirement beyond faith in Jesus betrays the Gospel.
Of course, it’s not quite that simple. Some profess Jesus but betray him with their lives. Jesus and Paul both teach that impenitent sinners and heretics should be excluded from the Church and from the table of communion. As Reformed Protestants say, the table must be fenced.
Even with that crucial qualification, Paul’s assault on Peter poses a bracing challenge to today’s church. It is common in every branch of the church for some believers to exclude other believers from the Lord’s table. Some Lutherans will commune only with Christians who hold to a Lutheran view of the real presence. Some Reformed churches require communicants to adhere to their Confessional standards. The Catholic Mass and the Orthodox Eucharist are reserved, with a few exceptions, for Catholics and Orthodox.
I cannot see how these exclusions pass the Pauline test. Catholics will say that they don’t add anything to Paul’s requirements. They exclude Protestants from the Mass because Protestantism is (at best) an inadequate expression of the apostolic faith; for Catholics, a credible confession of Jesus must include a confession of certain truths about the Church. Lutherans and some Reformed Christians will point to Paul’s warnings about “discerning the body” and ask Amos’s question: “Do men walk together unless they are in agreement?” All this avoids the central question: Do Catholics and Orthodox consider their Protestant friends Christians? Do Lutherans consider Reformed believers to be disciples of Jesus? If so, why aren’t they eating at the same table? Shouldn’t the one Lord have one people at one table?
This strikes me as missing the point on many levels, but I’ll let you do the analysis: What is wrong with this argument?