The difference is certainly not very important, as Mastricht and Moor commented; yet it is remarkable that many Lutherans preferred to say that the divine nature in the person of the Son became human, a formulation that is undoubtedly connected with their basic idea. But the Reformed favored the formulation that the person of the Son was immediately united with the human nature, and the divine nature was [therefore] mediately united with it. This is how the church fathers had taught earlier and how the church confessed it. The sixth Synod of Toledo (AD 638) declared that although the entire Trinity cooperates in the incarnation, inasmuch as all the works of the Trinity are inseparable, nevertheless “only (the Son) assumes human nature in the singularity of the person, not in the unity of the divine nature: in what is peculiar to the Son, not what is common to the Trinity.” Questions such as those were treated in scholasticism;¹⁰⁶ whether the Father and the Holy Spirit could have become a human, therefore, need not detain us. The Father could not be sent, for he is the first in order and is self-existent; the Spirit proceeds from the Son, succeeds him, and is sent by him. But the Son was the one suited for the incarnation. In the divine being he occupies the place between the Father and the Spirit, is by nature the Son and image of God, was mediator already in the first creation, and as Son could restore us to our position as children of God. Yet though subjectively and as it pertains to its end, the incarnation is peculiar only to the Son, still with respect to its origin, beginning, and effectiveness, it is a work of the whole Trinity. Christ was sent by the Father and conceived by the Holy Spirit. Reformed theology already expressed this truth in its doctrine of the pact of redemption (pactum salutis). The entire work of re-creation is not just a decree of God; it is rooted in the free and conscious consultation of the three persons. It is a personal, not a natural, work. In the Son, the Father is from all eternity the Father of his children; the Son is eternally their guarantor and mediator; the Holy Spirit is eternally their Comforter. Not just after the fall, not even first at the creation, but in eternity the foundations of the covenant of grace were laid. And the incarnation is not an incidental decree that emerged later: it was decided and determined from eternity. There was no time when the Son did not exist; there was also no time when the Son did not know he would assume and when he was not prepared to assume the human nature from the fallen race of Adam. The incarnation was prepared from eternity; it does not rest in the essence of God but in the person. It is not a necessity as in pantheism, but neither is it arbitrary or accidental as in Pelagianism.^[1]

^[1] Herman Bavinck, John Bolt, and John Vriend, Reformed Dogmatics: Sin and Salvation in Christ, vol. 3 (Grand Rapids, MI: Baker Academic, 2006), 276–277.