St. Paul warned the Corinthian Church to not unworthily partake of the Lord's Supper because, if they did, judgement would come upon them. In fact, as the Apostle highlights, some had already died because for their misuse. How many Christians consider these facts when thinking about the Lord's Supper? However, this ought not be a moment of fear and trembling, but a recognition of God's sovereign power even in passivity, which is something often missed.
Peter Chelcicky, that blessed Czech saint, understood the stakes of the debate before the Reformation reignited controversies over the Lord's Supper. Peter was a contemporary of the Hussite Wars, where the majority of the Czech people rose up against Rome after the martyrdom of Jan Hus. Various factions arose, but their common cause of unity was communion in two kinds, bread and wine.
Rome had placed sanctions on the laity partaking of the Cup. There was fear and dread wrapped around communion that not only did not many people partake of the cup (they both denied participation and were denied participation), but wouldn't partake of the bread. New justifications, with supposed miracles, allowed a form of communion by merely watching the Host being raised up. There were also fears related to the use of Communion. The "Heretics", some of whom either rejected the Real Presence or rejected Rome's clerical monopoly, would refuse communion, and would spit it out or throw it away when the priest was not looking. Others kept the elements for the purposes of what might be considered magic. People used the elements for charms and wards, trying to keep evil spirits away, create a love potion, or make a field fertile. There was also the fear of mishandling, where crumbs of the Lord's body would drop on the floor, where they could be stepped on or eaten by bugs or rodents. The Roman church attempted to crackdown through liturgical practices, such as placing the elements directly on the tongue.
On the other hand, a group of Hussites, known as the Taborites, were a nationalistic, Puritan faction (to put it anachronistically), who sought to purge the Czech church of corruptions. They were iconoclastic and attacked hierarchy. The Taborites also held to a theology that would become the mainstay of Calvinism. They believed that the Eucharist was only the Body of Christ if it was received in faith. If an unbeliever partook of the elements, they would only be eating bread.
Chelcicky, who sympathized with the Taborite wing, rejected their nationalism and their violence. But he also rejected their doctrine of the Lord's Supper. However, he also rejected the Roman variety as well. Both sides, though diametrically opposed, depended on a view of the Supper that saw the Lord as thoroughly passive, and made the power of God's word dependent upon those who would receive.
Rome, through refined doctrine of ex opere operato, had moved in a direction of what Charles Taylor described as "white magic". The church is the font of Christ's Body, whose priesthood is ordained with the power and the authority to worship God through the transubstantiation of bread and wine into the elements of the Lord. Chelcicky found this distasteful because it made God passive before Human words. It was not that the Lord was not present in the bread and wine, but that He was weak before Human schemes and designs. The emphasis was less on God, fulfilling His promise, than on His being summoned. This turned a Christian rite into a Pagan one, where the deity was summoned, dragged out of Heaven for Human need. However, as is clear from the entirety of Scripture, the true God sets the terms. He finds us before we seek. The Roman model put God in the backseat.
The Taborites, as proto-Calvinists of a sort, did the same through a different means. Rather than a proper priesthood and words of institution, the Taborites dragged God down through faith. It was now an internal, not external, medium to bring about God's fulfillment.
However, the key similarity was that both the Taborites and the Romanists both viewed divine presence in passiveness as weakness. The former articulated a theology that kept God away from the unclean and polluted. Thus, man could not impiously eat of the Body of God, because God would not allow such to take place. There's a sense where it would be shocking and disturbing to think God could be manipulated in such a way, and so it is clearly blasphemous. The latter, on the other hand, feared the possibility of misuse, whether for the purposes of practical witchcraft or by accident. Lest you think this is in the past, I read a Roman Catholic form post where a woman had a severely troubled conscience because her son, after eating the elements, threw up a couple minutes later. She didn't know if she committed a mortal sin by not trying to fish the remains out of the vomit. There's a sense that God will punish the abuse of His Son's flesh.
However, none of this is conveyed in St. Paul's warning. In fact, it was because, as he puts it, if one eats and drinks unworthily, he does so unto his own judgement. While the Roman view captures part of this, it does so in such a way that the Body of Christ is not the agent of judgement. Is Christ not supreme conqueror of death in His body? Then why would He be anxious if a witch took hold of Him, or a mouse came to nibble? Christ is not the one in danger, nor is there any possibility that His elements can be abused for other purposes. There is no promise to mice partaking of the Supper, nor is there a promise that if the bread is dropped in a potion it will make a girl fall in love with you. Christ is firmly in control of His own elements, acting in the way He sees fit to declare. For it is only because He tells us to celebrate the Lord's Supper, and declares that He is present in His Body and Blood, that we know to both celebrate it and to do it with care and reverence. It's this context Paul rebukes the Corinthians, for they scorned the poor in practicing the Supper, and by unworthily eating Christ brought the Judge straight into the depths of their inner bowels, both literally and metaphorically. They who abused the poor invited the Avenger of the Oppressed into their innermost home, and suffered the consequences.
Even as the Lord is present in unassuming bread and wine, it does not mean He is weak or powerless. In fact, He is made manifest as powerful when He is clothed in weakness. This is the plain witness of the gospel. When we draw near to Christ, partaking of His Body and Blood, we should know truly, we are in the presence of the King, and for those who have cast themselves before Him, we should find it a moment of exceeding joy. He has come to make His work known again, killing our sin and raising us to glory and honor.