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.