NINTH ARTICLE [III, Q. 2, Art. 9]

Whether the Union of the Two Natures in Christ Is the Greatest of All

Unions?

Objection 1: It would seem that the union of the two natures in

Christ is not the greatest of all unions. For what is united falls

short of the unity of what is one, since what is united is by

participation, but one is by essence. Now in created things there are

some that are simply one, as is shown especially in unity itself,

which is the principle of number. Therefore the union of which we are

speaking does not imply the greatest of all unions.

Obj. 2: Further, the greater the distance between things united, the

less the union. Now, the things united by this union are most

distant--namely, the Divine and human natures; for they are

infinitely apart. Therefore their union is the least of all.

Obj. 3: Further, from union there results one. But from the union of

soul and body in us there arises what is one in person and nature;

whereas from the union of the Divine and human nature there results

what is one in person only. Therefore the union of soul and body is

greater than that of the Divine and human natures; and hence the

union of which we speak does not imply the greatest unity.

_On the contrary,_ Augustine says (De Trin. i, 10) that "man is in

the Son of God, more than the Son in the Father." But the Son is in

the Father by unity of essence, and man is in the Son by the union of

the Incarnation. Therefore the union of the Incarnation is greater

than the unity of the Divine Essence, which nevertheless is the

greatest union; and thus the union of the Incarnation implies the

greatest unity.

_I answer that,_ Union implies the joining of several in some one

thing. Therefore the union of the Incarnation may be taken in two

ways: first, in regard to the things united; secondly, in regard to

that in which they are united. And in this regard this union has a

pre-eminence over other unions; for the unity of the Divine Person,

in which the two natures are united, is the greatest. But it has no

pre-eminence in regard to the things united.

Reply Obj. 1: The unity of the Divine Person is greater than

numerical unity, which is the principle of number. For the unity of a

Divine Person is an uncreated and self-subsisting unity, not received

into another by participation. Also, it is complete in itself, having

in itself whatever pertains to the nature of unity; and therefore it

is not compatible with the nature of a part, as in numerical unity,

which is a part of number, and which is shared in by the things

numbered. And hence in this respect the union of the Incarnation is

higher than numerical unity by reason of the unity of the Divine

Person, and not by reason of the human nature, which is not the unity

of the Divine Person, but is united to it.

Reply Obj. 2: This reason regards the things united, and not the

Person in Whom the union takes place.

Reply Obj. 3: The unity of the Divine Person is greater than the

unity of person and nature in us; and hence the union of the

Incarnation is greater than the union of soul and body in us.

And because what is urged in the argument "on the contrary" rests

upon what is untrue--namely, that the union of the Incarnation is

greater than the unity of the Divine Persons in Essence--we must say

to the authority of Augustine that the human nature is not more in

the Son of God than the Son of God in the Father, but much less. But

the man in some respects is more in the Son than the Son in the

Father--namely, inasmuch as the same suppositum is signified when I

say "man," meaning Christ, and when I say "Son of God"; whereas it is

not the same suppositum of Father and Son.

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Summa Theologica, Part III (Tertia Pars) From the Complete American Edition · 第 25 / 654 题