Nonsense. A mainstream Christian that loves the Lord is not unworthy to receive communion. Open communion churches like mine also have the same scripture. Haven’t seen one keel over yet.
I can appreciate arguments both in favor of Open Communion, and arguments in favor of Closed Communion.
As a Lutheran I have been part of churches which have been on opposite sides of this issue. Though I am, presently, a member of a church which practices Closed Communion.
In defense of Closed Communion, the central position isn't to deny other Christians that they are, indeed, Christians. Every Christian is a Christian by virtue of their faith in Christ and their baptism. All who are baptized are, indeed, the property of Jesus Christ; all who believe in Him belong to Him. The matter of Closed Communion, however, is ultimately about a couple matters (Everything that follows will be from an explicitly Lutheran perspective):
1. Confession. When we come to the Table of the Lord we are giving our "Amen" to a shared belief, we are con (together) fessing (declaring) that this is, indeed, the true body and blood of Jesus Christ which was broken and shed for us. The Table is where the Church proclaims her unity of faith--if we are not, indeed, in a state of unity of faith, then there is a sense in which we are betraying what the Table signifies; and if we are not confessing that this is the true body and true blood of Jesus then we are betraying the Table itself--for it is, indeed, the true body and true blood of Jesus Christ.
1b. Counter Argument: Since the Table is the true body and true blood of Jesus Christ, then when one partakes of the Table they receive the true body and true blood of Jesus, even if one does not recognize it; it remains the precious Means of Grace by which Christ offers Himself, and the forgiveness of our sins, and God's mercy remains delivered through the Means because the Means of Grace depends not on man's ability or intellect, but on God's word and promise. Since it is the Table of Christ, not the Church's Table, then Christ is Lord over His Table and whosoever partakes in this bread and partakes in this wine partakes of the body and blood of Christ which He freely offers. In the same way that, though an infant may not comprehend intellectually what happens in the precious gift of Baptism, but receives grace freely according to the word and promise of God; so does one who partakes of the Table receive freely what is freely offered. So that even though there is failure in understanding, there cannot be failure with God and His word.
2. There is the spiritual danger of not properly discerning the body (and blood) of the Lord in the Table and therefore one who comes to the Table not discerning Christ's own body, is (as the Apostle writes to the Corinthians) actually eating and drinking to their own destruction. Therefore while the Table is Christ's, and the Church is not master over the Table and only Christ is, the Church still have a responsibility to properly administer the Table--a servant must serve faithfully, a steward must steward properly. And Christ has entrusted His Table to His Church. Therefore the Church bears the weight of responsibility to administer the Sacrament rightly--and one of the ways she administers the Sacrament rightly is by insisting on a shared confession of faith; and that when the Church assembles around the Table, she is Confessing her Lord and Master; and that this is indeed His Table, His body, His blood, and that here therein is the forgiveness of sins and the mighty grace of God. For the Sacraments are, by God's word and command, about the strengthening and edifying of faith--and should the Church administer the Sacrament in such a way that injures faith rather than strengthens faith, then the Church becomes an unfaithful steward of the Lord's Table.
2b. Counter Argument: The Church, indeed, does bear the responsibility of steward and servant, being entrusted by the Lord His own Table. However, the eating and drinking to one's own destruction is not merely the failure to have a correct theological understanding of the Table; but is treated by the Apostle to the Corinthians as treating the Lord's Table flippantly--as he writes that many came eating and drinking to the point of some getting drunk even before everyone had come together. The proper stewardship of the Table, then, consists not in denying the Table to brothers and sisters who may lack a correct understanding of it; but in not mishandling the Table in such a way that it dishonors the Lord's body and blood, such as by treating the Table as though it were merely a ritual of no particular significance. Or by, in our assembly, treating the Lord's Table as though it were a common table (or worse, to treat the Lord's Table worse than we would even our own common dinner table).
2c. Counter to the Counter: It is precisely because of this danger of mishandling the Table that the Church must rightly insist that all who come to the Table know what the Table is: Of Whom they come before, for they come to the Table of the Lord, and it must be regarded with the utmost reverence. For when comes into the house of the king and sit at the king's table, one is obligated to regard the king as the king and the king's table as the king's table. For the Church to fail in that kind of stewardship would bring dishonor to the Lord, and dishonor His own body and blood. And it would invite dishonor; to treat the Table flippantly. If the Church treats the Lord's Table as though it were a common table, then all who approach the Table would view the Lord's Table as though it were common, and not the Lord's. The Church therefore bears responsibility to insist that the Table be honored and revered, for what is received is not mere ordinary bread and wine; but indeed the precious and holy and true body and blood of Jesus Christ, and the forgiveness of sins.
Addendum: I feel like I could continue presenting arguments and counter arguments (and counter-counter arguments). But I think, at the end of the day the real issue is this: If the Eucharist is, indeed, the Lord's body and blood (and not merely a memorial of His body and blood), then that radically changes how the Table is to be administered, viewed, and approached.
To that end, while I appreciate arguments from both sides. I do think, ultimately, the case for Closed Communion is strongest. Not treating the Sacrament like some fancy Hollywood VIP party; the point is not to say, "You lot over there aren't good enough for our party". Instead, it's about recognizing the Sacrament as, indeed, Christ's precious Table. The Table is closed, not because others are less Christian. The Table is closed because we should insist that all who come to the Table know that it is the Table of the Lord.
