G.K. Chesterton once wrote of George Bernard Shaw, “In some matters the difference between us seems to amount to this: that I very respectfully recognize that he disagrees with me, but he will not even allow me to disagree with him” (“Our Birthday,” G.K.s Weekly, 21st March, 1935; in The G.K. Chesterton Collection on Kindle).
Part of the difference between Lutherans and Reformed on the Sacrament of the Altar seems to amount to this: that while the Lutherans (most of the time) respectfully recognize that the Reformed disagree with us, the Reformed will not allow the Lutherans to disagree with them about the Supper. This is not a new phenomenon. All the way back to the earliest disagreements among the different confessions arising from the Reformation, the Lutherans made church fellowship the sine qua non of altar fellowship, and vice-versa. One necessarily entailed the other, just as it did from the very beginning of the Church of Christ on earth (see Elert, Eucharist and Church Fellowship). On the other hand, the non-Lutheran Reformed began, at least as early as 1631 at the French Synod of Charenton, to welcome Lutherans to Reformed tables. Whether it was because sharing mere bread and wine does not require any agreement on what is happening to and for Christians there, or whether it was because the Lord’s Supper didn’t belong to the essential core of the Christian Faith (Zwingli), the Reformed have never understood the Lutheran objection to a shared Supper. They will not allow the Lutherans to disagree with them. (Regarding the myriad contradictions that serious Reformed see in Lutheran teaching, see Hermann Sasse, Here We Stand, 105ff.)
Besides the current cultural context, which inevitably reduces and minimizes confessional differences, the Reformed descendants of Calvin, Zwingli, Bucer, et al. find the Lutheran position to be a loveless one. In the uniform (until recently) and historical Lutheran practice of sharing the communion of the Lord only when confessional unity under the Scriptures is recognized, the Reformed hear only an accusation against them that they are not Christians or not “Christian enough.” But it is at precisely this point where the Lutherans feel the exasperation of Chesterton when arguing with Shaw: we simply want to recognize the real and substantial gulf between the Lutheran and Reformed positions, and they will not even allow us to disagree with them. The Lutherans believe that the two positions are as far apart as heaven and earth: the bare fact of whether we eat Christ’s Body and Blood with the bread and wine, or whether we do not, is–quite literally–everything. This is why, for Lutherans, “all questions of the life and teaching of the church ultimately [lead] to the question of the Lord’s Supper” (Sasse, “Why Hold Fast to the Lutheran Doctrine of the Lord’s Supper?” The Lonely Way, I:453).
Finally, we simply want to be honest, and state that there is an irreconcilable contradiction between those who confess Christ’s Body and Blood eaten and drunk by everyone (even, God forbid, an unbeliever) who communes, and those who say that there is only bread and wine eaten and drunk by some or all. This is not a difference in how Christ’s Body and Blood are present, but whether they are. Lutherans have never confessed a particular mode, means, or mechanism of describing Christ’s Presence in the Sacrament (e.g., “consubstantiation”). But Lutherans have always confessed that His Body and Blood are eaten and drunk by everyone, quite apart from an individual’s faith. This is what Jesus says, and our horizontal unity around the altar depends on making the same confession about Jesus’ own words. That is what “confession” means: saying the same thing. And that is what “communion” means: union-with. Union with Jesus in His Body and Blood (which is impossible if His Body and Blood are not actually there); and union with the other members of His Body precisely because we all share the same Christ as He gives Himself to us. This, and nothing else, is the cause of “closed Communion.” Closed to all who refuse to confess with us the simple words of Jesus, but open to all who receive these words with faith and joy. We cannot force anyone to accept this confession, but we do ask that those who don’t accept it allow us to respectfully disagree with them.