children of men"; and hence
there would seem some fitness in the union of the Son of God with
human nature.

_I answer that,_ A thing is said to be assumable as being capable of
being assumed by a Divine Person, and this capability cannot be taken
with reference to the natural passive power, which does not extend to
what transcends the natural order, as the personal union of a
creature with God transcends it. Hence it follows that a thing is
said to be assumable according to some fitness for such a union. Now
this fitness in human nature may be taken from two things, viz.
according to its dignity, and according to its need. According to its
dignity, because human nature, as being rational and intellectual,
was made for attaining to the Word to some extent by its operation,
viz. by knowing and loving Him. According to its need--because it
stood in need of restoration, having fallen under original sin. Now
these two things belong to human nature alone. For in the irrational
creature the fitness of dignity is wanting, and in the angelic nature
the aforesaid fitness of need is wanting. Hence it follows that only
human nature was assumable.

Reply Obj. 1: Creatures are said to be "such" with reference to their
proper causes, not with reference to what belongs to them from their
first and universal causes; thus we call a disease incurable, not
that it cannot be cured by God, but that it cannot be cured by the
proper principles of the subject. Therefore a creature is said to be
not assumable, not as if we withdrew anything from the power of God,
but in order to show the condition of the creature, which has no
capability for this.

Reply Obj. 2: The likeness of image is found in human nature,
forasmuch as it is capable of God, viz. by attaining to Him through
its own operation of knowledge and love. But the likeness of trace
regards only a representation by Divine impression, existing in the
creature, and does not imply that the irrational creature, in which
such a likeness is, can attain to God by its own operation alone. For
what does not come up to the less, has no fitness for the greater; as
a body which is not fitted to be perfected by a sensitive soul is
much less fitted for an intellectual soul. Now much greater and more
perfect is the union with God in personal being than the union by
operation. And hence the irrational creature which falls short of the
union with God by operation has no fitness to be united with Hi