Obj. 2: Further, Abraham believed that Christ would be born,
according to John 8:56: "Abraham your father rejoiced that he might
see My day: he saw it, and was glad." But after the time of Abraham,
God might not have taken flesh, for it was merely because He willed
that He did, so that what Abraham believed about Christ would have
been false. Therefore the object of faith can be something false.

Obj. 3: Further, the ancients believed in the future birth of Christ,
and many continued so to believe, until they heard the preaching of
the Gospel. Now, when once Christ was born, even before He began to
preach, it was false that Christ was yet to be born. Therefore
something false can come under faith.

Obj. 4: Further, it is a matter of faith, that one should believe
that the true Body of Christ is contained in the Sacrament of the
altar. But it might happen that the bread was not rightly
consecrated, and that there was not Christ's true Body there, but
only bread. Therefore something false can come under faith.

_On the contrary,_ No virtue that perfects the intellect is related
to the false, considered as the evil of the intellect, as the
Philosopher declares (Ethic. vi, 2). Now faith is a virtue that
perfects the intellect, as we shall show further on (Q. 4, AA. 2, 5).
Therefore nothing false can come under it.

_I answer that,_ Nothing comes under any power, habit or act, except by
means of the formal aspect of the object: thus color cannot be seen
except by means of light, and a conclusion cannot be known save
through the mean of demonstration. Now it has been stated (A. 1)