denominated from the subject
moved, but from the terminus of the movement, whence the subject has
its species. For this reason nativity is not denominated from the
person born, but from nature, which is the terminus of nativity.

Reply Obj. 3: Nature, properly speaking, does not begin to exist:
rather is it the person that begins to exist in some nature. Because,
as stated above, nature designates that by which something is;
whereas person designates something as having subsistent being.
_______________________

SECOND ARTICLE [III, Q. 35, Art. 2]

Whether a Temporal Nativity Should Be Attributed to Christ?

Objection 1: It would seem that temporal nativity is not to be
attributed to Christ. For "to be born is a certain movement of a
thing that did not exist before it was born, which movement procures
for it the benefit of existence" [*Cf. Augustine, De Unit. Trin.
xii]. But Christ was from all eternity. Therefore He could not be
born in time.

Obj. 2: Further, what is perfect in itself needs not to be born. But
the Person of the Son of God was perfect from eternity. Therefore He
needs not to be born in time. Therefore it seems that He had no
temporal birth.

Obj. 3: Further, properly speaking, nativity regards the person. But
in Christ there is only one person. Therefore in Christ there is but
one nativity.

Obj. 4: Further, what is born by two nativities is born twice. But
this proposition is false; "Christ was born twice": because the
nativity whereby He was born of the Father suffers no interruption;
since it is eternal. Whereas interruption is required to warrant the
use of the adverb "twice": for a man is said to run twice whose
running is interrupted. Therefore it seems that we should not admit a
double nativity in Christ.

_On the contrary,_ Damascene says (De Fide Orth. iii): "We confess
two nativities in Christ: one of the Father--eternal; and one which
occurred in these latter times for our sake."

_I answer that,_ As stated above (A. 1), nature is compared to
nativity, as the terminus to movement or change. Now, movement is
diversified according to the diversity of its termini, as the
Philosopher shows (Phys. v). But, in Christ there is a twofold
nature: one which He received of the Father from eternity, the other
which He received from His Mother in time. Therefore we must needs
attribute to Christ a twofold nativity: one by which He was born of
the Father from all eternity; one by which He was