On Holy Thursday we hear Christ’s stunning words: “This is my body.” Our minds struggle to comprehend how the creator of the universe makes himself become really present. To wrap our minds around this miracle, several principles derived from St. Thomas Aquinas may help.
First, the accidents of the bread and wine are found before and after the consecration. Accidents are real, not an illusion. The accidents are the sensory appearance of an object. Second, we really receive Christ’s Body and Blood at the Mass. At the same time Christ remains in heaven. Third, a single body cannot be extended with its quantity in two places at once with its own accidents. Hence, this is why we say the accidents of bread and wine remain. Fourth, an object or a person comes to be in a place either by a change of place (called locomotion) or by the conversion of one thing into another (called substantial change). Finally, at the Last Supper Christ means what he says.
For change to occur there must be something at the beginning of the process and something at the end of the process (change does not come from nothing). In Transubstantiation, Christ’s body and blood do not change (if they did, then Christ would be constantly recreated at every Mass, which is impossible). Instead, the substance of bread and wine changes. The bread and wine are not annihilated and then Christ is present, rather the bread and wine must be there for a change to occur.
No substance of the bread and wine remain (an idea called impanation), since this would imply a weakness on the part of Christ. Finally, the bread and wine must be substantially changed, otherwise Christ would be present by locomotion, which contradicts principles two to four above. In short on Holy Thursday and at every Mass we receive Christ’s body and blood under the appearance of bread and wine.
