The objection
If every divine work belongs jointly to Father, Son and Spirit, either all three would have to become human or incarnation could not be a divine work.
1. The objection equates cause and personal reference
“Who brings about incarnation?” and “Who lives as a human?” are not the same question. God's undivided activity answers the first. The statement “the Son became flesh” answers the second. A shared cause does not entail that each person is also the result of this activity in the same way.
Thomas expressly formulates this distinction: The divine power through which human nature is assumed is shared; union with this human nature subsists in the Son's person.[1]
2. The biblical texts connect precisely these two sides
Luke 1,35 describes the activity of the Holy Spirit and the Most High's power at Jesus' human conception. Galatians 4,4 says that God sent his Son, born of a woman. John 1,14 names the Logos as the one who became flesh.
The texts do not say the Spirit assumed humanity because he acts in its coming into being. Nor does the sender become the sent one. Shared divine action and the Son's particular incarnation already stand together in the New Testament's presentation.
3. Undivided action means no uniformity of relationships
The Father sends the Son; the Son is sent. These statements describe no two competing creative powers. They designate different personal relationships within the one divine action. The Son is no external recipient of an alien divine being.
Two kinds of presence must therefore also be distinguished. According to John 14,23, Father and Son dwell with believers. It does not follow that every believer is an incarnation of God. God's presence and efficacy are not identical with the unique personal union in Christ.
4. The distinction holds through to the cross
The Son suffers and dies according to his assumed human nature. The Father was not crucified. At the same time, the saving event is no private action of a God detached from the Father. The Father sends, the Son gives himself, the Spirit acts in the divine work of salvation.
The alleged contradiction arises only if every result brought about by God had to be attributed indiscriminately to every divine person. This rule is neither logically self-evident nor biblically taught. It would already eliminate the real distinction of Father, Son and Spirit by presupposition.
5. How shared works make particular persons known
“Appropriation” means: An attribute common to all three persons is particularly assigned to one for clarification—for example power to the Father, wisdom to the Son and love to the Spirit. The Father thereby possesses no less wisdom and the Son no less love. Thomas explains these assignments as an aid to understanding the persons through known divine perfections.[2] An exclusively personal statement must be distinguished from this: Only the Son became human. This is no mere linguistic emphasis of a humanity equally present in all.
One therefore cannot read from a natural event which divine person alone acted. Shared creative power does not by itself prove threefoldness.[3] God's Word identifies the persons within their undivided activity: The Father sends the Son; the Son becomes human; the Spirit attests and glorifies him. Revelation discloses more here than merely observing an effect. Shared efficacy therefore does not make personal differences disappear.
Biblical texts in context
Sources and further study
- Thomas Aquinas, Summa theologiaeIII, q. 3, a. 4: distinction between the shared act of assumption and the person in whom the union subsists.
- Thomas Aquinas, Summa theologiaeI, q. 39, a. 7–8: appropriation of shared essential attributes to individual persons.
- Thomas Aquinas, Summa theologiaeI, q. 32, a. 1: shared creative power alone permits no deduction of personal threefoldness.