s, "which
is called weak, because it does not justify perfectly." But grace
justifies perfectly. Therefore the sacraments of the old Law did not
confer grace.

_I answer that,_ It cannot be said that the sacraments of the Old Law
conferred sanctifying grace of themselves, i.e. by their own power:
since thus Christ's Passion would not have been necessary, according
to Gal. 2:21: "If justice be by the Law, then Christ died in vain."

But neither can it be said that they derived the power of conferring
sanctifying grace from Christ's Passion. For as it was stated above
(A. 5), the power of Christ's Passion is united to us by faith and
the sacraments, but in different ways; because the link that comes
from faith is produced by an act of the soul; whereas the link that
comes from the sacraments, is produced by making use of exterior
things. Now nothing hinders that which is subsequent in point of
time, from causing movement, even before it exists in reality, in so
far as it pre-exists in an act of the soul: thus the end, which is
subsequent in point of time, moves the agent in so far as it is
apprehended and desired by him. On the other hand, what does not yet
actually exist, does not cause movement if we consider the use of
exterior things. Consequently, the efficient cause cannot in point of
time come into existence after causing movement, as does the final
cause. It is therefore clear that the sacraments of the New Law do
reasonably derive the power of justification from Christ's Passion,
which is the cause of man's righteousness; whereas the sacraments of
the Old Law did not.

Nevertheless the Fathers of old were justified by faith in Christ's
Passion, just as we are. And the sacraments of the old Law were a
kind of protestation of that faith, inasmuch as they signified
Christ's Passion and its effects. It is therefore manifest that the
sacraments of the Old Law were not endowed with any power by which
they conduced to the bestowal of justifying grace: and they merely
signified faith by which men were justified.

Reply Obj. 1: The Fathers of old had faith in the future Passion of
Christ, which, inasmuch as it was apprehended by the mind, was able
to justify them. But we have faith in the past Passion of Christ,
which is able to justify, also by the real use of sacramental things
as stated above.

Reply Obj. 2: That sanctification was but a figure: for they were
said to be sanctified forasmuch as they gave themselv