The Incarnation is the mystery of God and humanity dwelling together in unbroken, inseparable union. Christ has taken on our full humanity, not as a vessel or garment to be cast aside but as that which he has become, without in any way detracting from his full divinity. For “The Word became flesh and made his dwelling among us. We have seen his glory, the glory of the one and only Son, who came from the Father, full of grace and truth” (John 1:14). This union is not a blending or confusion of natures but a co-inherence — a mutual indwelling — such that wherever the Son is, both divinity and humanity are fully present. St. Maximus the Confessor speaks of this great and encompassing mystery:
By his gracious condescension God became man and is called man for the sake of man and by exchanging his condition for ours revealed the power that elevates man to God through his love for God and brings God down to man because of his love for man. By this blessed inversion, man is made God by divinization and God is made man by hominization. For the Word of God and God wills always and in all things to accomplish the mystery of his embodiment. (Ambigua 7)
“God became man” in order to save lost man, and — after he had united through Himself the natural fissures running through the general nature of the universe ... to fulfill the great purpose of God the Father, recapitulating all things, both in heaven and on earth, in Himself, in whom they also had been created. (Ambigua 41)
The deified person, while remaining completely human in nature, both in body and soul, becomes wholly God in both body and soul, through grace and the divine brightness of the beatifying glory that permeates the whole person. (Ambigua; Patrologia Graeca 91, 1088)
In the Incarnation, Christ did not become merely one of us but one with us. He is not simply one man among many but the one in whom God’s eternal purpose to bring unity to all in heaven and on earth — all are summed up in Christ (Ephesians 1:9-10). Christ is in all and all are in Christ. This mutual indwelling is the heart of salvation.
Christ has united human nature to himself, and so is present in all humanity, sustaining each one of us. In him, humanity is healed, restored, and brought into union with God. As St. Gregory of Nazianzus says, “That which he has not assumed he has not healed; but that which is united to his Godhead is also saved” (Epistle 101, To Cledonius).
The Co-Inherence of Divinity and Humanity in our Lord Jesus Christ means that salvation is not some abstract, legal declaration, but a real and transformative union. Through such tangible means as baptism and the Eucharist, we are joined to Christ’s death and resurrection, and by the Holy Spirit we share in his divine life. “It is no longer I who live,” says Paul, “but Christ who lives in me” (Galatians 2:20). “His divine power has given to us all things that pertain to life and godliness, through the knowledge of him who called us by glory and virtue, by which have been given to us exceedingly great and precious promises, that through these you may be partakers of the divine nature” (2 Peter 1:3-4).
The Incarnation is the co-inherence,
the interpenetration, the mutual indwelling
of divinity and humanity, of God and humankind.
It means Christ is in all and all are in Christ.
