Pope Paul, in Mysterium Fidei wrote (no.39):
|"and so it would be wrong for anyone to try to explain this manner of presence by dreaming up a so-called "pneumatic" nature of the glorious body of Christ that would be present everywhere".
"The Liturgy of the Eucharist can be identified as a four-fold movement by which bread and wine as well as the worshipping assembly are changed and transformed into the body and blood of Christ".
"Through the praying of the Eucharistic Prayer, the bread and wine as well as the entire worshipping assembly are changed and transformed into the Eucharistic Presence of Jesus".
"As the worshipping assembly processes to the reception of the body and blood of Christ, in the very act of procession communion is occurring. How the community makes its way to eat and drink of the Eucharist reveals as much about the Eucharist as the Eucharistic food itself".
"As the worshipping assembly processes together in reverence and song, the food that is shared, is changing and transforming. Standing together until the last person has been fed, the assembly is transformed from individualism into one body".
The full document can be found here. Pope Paul VI's encyclical on the Holy Eucharist can be found here.