Why should communion be "closed"?

Question

Both the Roman Catholic Church (RCC) and the Lutheran Church Missouri Synod (LCMS) and other denominations have restrictions upon who is allowed to take communion alongside current members. Even though congregations exist in both churches wherein individual pastors will sometimes ignore this rule, the doctrine of each prohibits non-members from taking communion alongside members. Both churches require those who desire to take communion to attend classes and become full members before they are allowed to take communion. (Obvious oversimplification, but this is the gist of it.) But is this practice not in direct opposition to the overall and undeniable messages of the Gospels, which say our principal responsibilities are to love God above all else and love our neighbors as ourselves?

I am not seeking the answer I already know, which is that both churches have doctrine that more-or-less states that it would be sinful (and harmful for the person receiving it) to allow someone to take communion if they did not understand the Eucharist exactly as each of these churches understands it (which oddly enough is different in each case).

In 1983, the LCMS justified its position on the Eucharist and stated that it is providing justification "so that the church's posture does not appear to be a mere institutional accruement." Then it goes on to offer several institutional accruements. If it is a duck, no amount of confirming one's desire to not be a duck will change it from being a duck. A similar posture is seen in the RCC doctrine, although I am less familiar with their doctrinal writings so I won't quote them.

To my knowledge, and I am sure someone will set me straight, Jesus had little to say about the nature of the Eucharist or the nature of those with whom it should be shared. His only instructions on the matter was "Do this for the remembrance of me" and his only descriptions of either portion of the meal was "This is my body, which is given for you." and "This cup is the New Covenant in my blood..." and if we use Luke, it was "poured out for many." There is also John 6:54-58 where Jesus addresses the traditional Jewish community and seems to make taking part in communion a command for everyone to obey, not just those who believe in a particular doctrine, although this occurred at a different time and place than the other instruction.

I understand that Paul had some things to say about the Eucharist in other New Testament writings, but if we focus only upon the words of Jesus, which should always be kept sacred to a Christian, what is the problem with open communion? Isn't the potential harm that could be done far outweighed by the potential good that could be done by allowing someone who might be "on the fence" to take part in a powerful sacrament of forgiveness and remembrance? Hasn't Jesus commanded that we do so? Is it not a sin to withhold communion from those who might think a little differently about the specific nature of the Eucharist? Does this practice not insult the new believer who, like everyone other Christian, had to ask Jesus to enter their heart (whether or not we knew it when it happened)? It would seem that merely having access to information about something that is intentionally left vague by Jesus in the first place should not be the controlling factor in whether a sacrament is received.

Even if I agree with the general concepts for why communion should be closed (people should understand its purpose so as to discourage heresies), I cannot extend that agreement to a belief that only those who understand the Eucharist like any particular church has interpreted it should be allowed to take part in a remembrance of Jesus so long as their heart is in a place of humility, contrition, and a sincere belief that Jesus Christ died and rose again to become their personal savior.

Please explain how scripture says we should withhold this sacrament from people who have a different understanding of the nature of the Eucharist after it is blessed by a pastor/priest. Please explain why I am wrong in my belief that Jesus instituted the Lord's Supper for everyone, not just those who think like we do about insignificant details. To me, that is exactly what Jesus preached at length against doing in the book of Matthew when he had some pretty angry words for the Pharisees who were all show and no faith.

Answer 1

Is it not a sin to withhold communion from those who might think a little differently about the specific nature of the Eucharist?

I would argue that there is a misconception here (and this seems to be the root of your question).

As one source (see below) says: "The celebration of Holy Communion is also a public act of confession. When you receive the Sacrament at a church's altar, you are giving public testimony that you agree with that church's doctrinal position." (Emphasis added.) Another: "Communion creates and defines our community, our being one with one another in Christ". Another: "Those Christians who remain outside of [our] Church are, by definition, not in full union (communion) with [our] Church" and "[if those people commune with us, they] are saying with their body, 'I am in full union with the Church,' when in fact they are not. Reception of the greatest gift Christ intends to give to us therefore becomes an act of dishonesty and occasion of sin." Still another: "It would be shameful hypocrisy on our part if we would have those who actually profess a different faith than we do join us at the Lord's Altar" and "Close communion seeks to prevent a profession of confessional unity in faith where there is, in fact, disunity and disagreement".

Practicing closed communion is not the same as forbidding someone from taking communion. It isn't saying "you may not have communion", but "it is not appropriate that you should take communion with us". The very word suggests why this should be: communion is an expression of unity in faith. If one does not have unity in faith with another, one should not partake of communion what that other person, but with other Christians with which one does share faith. For the same reason, most Christians who practice closed communion would not merely exclude Christians of another faith from their own churches, but would exclude themselves from communing outside their church. (Note that "church" here is roughly synonymous with "denomination", not a specific congregation.)

Further reading (mostly taken from Google):

• General:
  • https://en.wikipedia.org/wiki/Closed_communion
• Catholics specifically:
  • https://www.catholic365.com/article/1795/explaining-closed-communion-to-noncatholics.html
• Orthodox specifically:
  • https://blogs.ancientfaith.com/prayingintherain/2018/03/on-closed-communion/
  • https://www.goarch.org/-/why-non-orthodox-are-excluded-from-the-sacrament-of-holy-communion
  • https://www.oca.org/reflections/fr.-john-breck/why-not-open-communion
• (Confessional) Lutherans specifically:
  • https://files.lcms.org/wl/?id=eG8O2Xr5xpwK89iZAT0aiiwFt016ed3l
  • https://steadfastlutherans.org/pdf/AnExplanationOfClosedCommunion.pdf
  • https://www.google.com/search?q=why+wels+closed+communion (WELS seems to have quite a few [semi-]official articles on the subject)

Note that, from what I know / can tell, the stance on closed communion of all of these bodies is fairly consistent, despite their doctrines having other (sometimes quite extreme) differences. (All also note that "open" communion is a modern invention of non-Lutheran protestant churches that was never practiced in the historical church prior to the reformation.)

Answer 2

The idea of a closed communion is very old. We can find Justin Martyr writing c150ad saying this:

And this food is called among us Εὐχαριστία1910 [the Eucharist], of which no one is allowed to partake but the man who believes that the things which we teach are true, and who has been washed with the washing that is for the remission of sins, and unto regeneration, and who is so living as Christ has enjoined. For not as common bread and common drink do we receive these; but in like manner as Jesus Christ our Saviour, having been made flesh by the Word of God, had both flesh and blood for our salvation, so likewise have we been taught that the food which is blessed by the prayer of His word, and from which our blood and flesh by transmutation are nourished, is the flesh and blood of that Jesus who was made flesh.

The footnote to this paragraph says this:

1911 This passage is claimed alike by Calvinists, Lutherans, and Romanists; and, indeed, the language is so inexact, that each party may plausibly maintain that their own opinion is advocated by it. [But the same might be said of the words of our Lord himself; and, if such widely separated Christians can all adopt this passage, who can be sorry?] The expression, “the prayer of His word,” or of the word we have from Him, seems to signify the prayer pronounced over the elements, in imitation of our Lord’s thanksgiving before breaking the bread. [I must dissent from the opinion that the language is “inexact:” he expresses himself naturally as one who believes it is bread, but yet not “common bread.” So Gelasius, Bishop of Rome (a.d. 490), “By the sacraments we are made partakers of the divine nature, and yet the substance and nature of bread and wine do not cease to be in them,” etc. (See original in Bingham’s Antiquities, book xv. cap. 5. See Chryost., Epist. ad. Cæsarium, tom. iii. p. 753. Ed. Migne.) Those desirous to pursue this inquiry will find the Patristic authorities in Historia Transubstantionis Papalis, etc., Edidit F. Meyrick, Oxford, 1858. The famous tractate of Ratranin (a.d. 840) was published at Oxford, 1838, with the homily of Ælfric (a.d. 960) in a cheap edition.] https://ccel.org/ccel/schaff/anf01/anf01.viii.ii.lxvi.html

This of course begs the question about exactly what was believed, but still, the idea of closed communion was exhibited.