whereby His body was
fashioned, it was impossible for anything derived from His body to
have the instrumental power of forming that very body. Likewise in
creation there was no term wherein the instrumental action of a
creature could be received. Consequently there is no comparison.

Reply Obj. 3: The aforesaid words, which work the consecration,
operate sacramentally. Consequently, the converting power latent
under the forms of these sacraments follows the meaning, which is
terminated in the uttering of the last word. And therefore the
aforesaid words have this power in the last instant of their being
uttered, taken in conjunction with those uttered before. And this
power is simple by reason of the thing signified, although there be
composition in the words uttered outwardly.
_______________________

FIFTH ARTICLE [III, Q. 78, Art. 5]

Whether the Aforesaid Expressions Are True?

Objection 1: It seems that the aforesaid expressions are not true.
Because when we say: "This is My body," the word "this" designates a
substance. But according to what was said above (AA. 1, 4, ad 3; Q.
75, AA. 2, 7), when the pronoun "this" is spoken, the substance of
the bread is still there, because the transubstantiation takes place
in the last instant of pronouncing the words. But it is false to say:
"Bread is Christ's body." Consequently this expression, "This is My
body," is false.

Obj. 2: Further, the pronoun "this" appeals to the senses. But the
sensible species in this sacrament are neither Christ's body nor even
its accidents. Therefore this expression, "This is My body," cannot
be true.

Obj. 3: Further, as was observed above (A. 4, ad 3), these words, by
their signification, effect the change of the bread into the body of
Christ. But an effective cause is understood as preceding its effect.
Therefore the meaning of these words is understood as preceding the
change of the bread into the body of Christ. But previous to the
change this expression, "This is My body," is false. Therefore the
expression is to be judged as false simply; and the same reason holds
good of the other phrase: "This is the chalice of My blood," etc.

_On the contrary,_ These words are pronounced in the person of
Christ, Who says of Himself (John 14:6): "I am the truth."

_I answer that,_ There have been many opinions on this point. Some
have said that in this expression, "This is My body," the word "this"
implies demonstration as conceived, and n