In the eyes of Martin Luther, the most essential division between himself and the group of reformers in Zurich under Ulrich Zwingli was in the doctrine of the Lord’s Supper. Luther, coming from a monastic background held on to much that he was taught within the Roman church. However, Zwingli, coming from more of a humanistic background, largely abandoned accepted church practice and doctrine, including their sacramental emphasis. Luther’s reformation was from within the church, while Zwingli was much quicker to abandon Rome. Zwingli held to a symbolic view of the supper. The bread and wine simply represented Christ’s body and blood. For Luther, Christ’s body and blood were truly communicated to the recipient.
The issues that divided the Reformed and Lutheran church from the beginning were not merely about the presence of Christ within the Eucharist. For Luther, Zwingli’s denial of the communicatio idiomatum (the communication of attributes) was a profound Christological error. Ancient Chalcedonian Christology had emphasized not only the separation of the two natures but also the unity of the person of Christ. Since Zwingli denied that an action performed by one nature could be attributed to the other, Luther accused him of Nestorianism. The old Nestorian heresy denied that Mary was to be called theotokos. (Mother of God) This was because technically speaking, Mary was the mother of the human nature of Christ, not the divine. Patristic divines saw this as making Christ into two separate persons, one human and one divine. At the council of Ephesus, led by Cyril of Alexandria, this was declared a damnable heresy.
Essentially Zwingli held to the same idea in Luther’s mind. Luther believed that the human nature of Christ had communicated omnipresence, thus could be present in the Lord’s Supper. Zwingli denied this saying that the finite was not capable of the infinite. The Lutheran divines saw this as a dangerous principle because taken to its logical conclusion; the human nature of Jesus would be incapable of the infinite God, thus denying the incarnation. For Luther, Zwingli’s doctrine was not arrived at through Biblical exegesis but by fallen human reason.
At the Colloquy of Marburg, these issues were debated by Luther and his supporters and Zwingli with his supporters. They came to an agreement on almost all other theological issues. When it came to the issue of the supper, the debate became heated. After hours of intense discussion, Luther began banging his fist on the table and yelling, “Hoc est corpus mayem!” (This is my body.) For Luther, these words of Christ were decisive. After the colloquy had ended unsuccessfully, Zwingli reached out to shake Luther’s hand. Luther refused. This one act signified that there would not be a union between the two parties. The issue of the Lord’s Supper was too essential to be compromised on.