ADOPTION, SUPERNATURAL. – Among the New Testament hagiographers, only St. Paul uses the juridical term adoption (υἱοθεσία) and elevates its meaning to the supernatural order. Writing to the Christians of Rome (Rom. 8:15 ff.), he says: “You have received the spirit of adoption as sons, by which we cry: Abba! Father! For the same Spirit bears witness to our spirit that we are children of God. And if children, then heirs, heirs indeed of God and co-heirs of Christ.”
In this text all the characteristics of supernatural adoption are summarized, which the Fathers and theologians will take care to illustrate and develop. This adoption is not resolved into a juridical fiction, as is human adoption, but into a true reality, deriving from a mysterious rebirth, a true regeneration of man by God. St. John speaks of it repeatedly with a realism that strikes home: “The Word,” he says in the prologue of his Gospel, “to those who received him and believed in him gave the power to become children of God, who were born of God, not of flesh and blood.” And in chap. 3 he reports the words that Jesus addressed to Nicodemus: “Unless one is born anew of water and the Spirit” (baptism). Finally, in 1 John 3:1, it is written: “See what love the Father has given us, that we should be called and really be children of God.”
Evidently here and in parallel texts it is not a question of physical, natural generation, nor even of creation, but of a regeneration of the human spirit made a partaker of the light and life of God, indeed of the divine nature itself, according to the energetic expression of St. Peter (2 Pet. 1:4). This rebirth, which St. Paul calls (2 Cor. 5:17) καινὴ κτίσις, that is, a new creation in Christ, is effected by means of grace, which establishes a vital communion with God (John 6:57), who comes to dwell in the sanctified soul (ibid., 14:23).
The Fathers, especially the Eastern ones, translate these lofty concepts into an expression that seems bold: deification. By it man enters into the sphere of the Divinity, into the bosom of the divine family, and thus acquires the right to inherit the divine riches. And all this is accomplished by virtue of the Incarnation and the Redemption of the Word. This profound thought recurs often in the writings of the Fathers: “The Word, the natural Son of God, becomes the Son of man, so that man may become the adopted son of God, the brother of Christ.” Thus St. Irenaeus, Athanasius, Cyril of Alexandria, Augustine, the latter of whom gathers the tradition into a fine passage in De Civitate Dei, 21.15.
In conclusion, supernatural adoption, according to Catholic doctrine, is an imitation of the natural sonship of the Word: He is Son of God by nature, man becomes son of God by grace. Regeneration and spiritual rebirth by the power of Christ the Redeemer; the fatherhood of God, who stoops to embrace again His creature made His daughter, putting into her heart the certainty of an infinite inheritance: these are the elements of supernatural adoption, which also constitute the intimate fabric of the evangelical message.