THIS IS MY BODY. See the annotations on the same words of consecration, Matthew xxvi. 26.; Mark xiv. 22. and 1 Corinthians xi. 24.

Do this for a commemoration of me. By these words he gave a power and precept to them, and their successors, to all bishops and priests, to consecrate and offer up the same; yet so, that they are only the ministers and instruments of Jesus Christ, who instituted this sacrifice, this and all other sacraments, who is the chief and principal Priest, or offerer. It is Christ that chiefly consecrates and changes the elements of bread and wine into his own body and blood; it is he that chiefly and principally forgiveth sins in the sacraments of baptism, penance, &c. It is what St. Augustine so often repeats against the Donatists, that it is Christ that baptizeth, though the instrumental minister be a sinner or a heretic; and this is what all Catholics confess and profess.

The holy sacrifice and sacrament is to be offered and received with a devout and grateful remembrance of Christ’s benefits, and especially of his sufferings and death for all mankind. But to teach that it is a bare, though devout memorial, or a remembrance only, so as to exclude the real presence of Christ, under the outward appearances of bread and wine, is inconsistent with the constant belief and consent of all Christian churches, both of the west and east, and contradicts the plain words of Christ. The learned bishop of Meaux, in his Exposition of the Catholic Faith, desires all Christians to take notice, that Christ does not command them to remember him, but to take his body and blood with a remembrance of him, and his benefits: this is the import of all the words, put together. This is my body: this is my blood: do this in, for, or with a remembrance of me. (Witham)

This sacrifice and sacrament is to be continued in the Church to the end of the world, to shew forth the death of Christ, until he cometh. But this commemoration, or remembrance, is by no means inconsistent with the real presence of his body and blood, under these sacramental veils, which represent his death; on the contrary, it is the manner that he himself hath commanded, of commemorating and celebrating his death, by offering in sacrifice, and receiving in the sacrament, that body and blood by which we were redeemed. (Challoner)

Which is given, &c. He does not say, which shall be offered for you, but which is offered;[2] because it was already a true sacrifice, in which Christ was truly present which he offered in advance to his eternal Father, before that which he was going to offer the next day, in a different manner, on the cross. This sacrifice was the consummation of the figurative Pasch, and the promise or pledge of the bloody offering, which Christ would make on the cross. ... It was not the mere figure of his body, which was crucified, but the true body and the true blood. In the same manner it is both the one and the other which are given, and really present, in the Eucharist. (Calmet)

To renew the memory of what I have this day done, in giving you my body; and what I shall do to-morrow, in delivering my blood and my life for the whole world, do you hereafter what you now see me do. Take bread, break it, sand say, This is my body; and it will become so really and truly, as it now is in my hands. (Calmet)