Is it the Grace of God that gives us this human nature?
EVERY work of God in Creation is generally termed a “Grace” in patristic, Catholic, Orthodox theology. In him and through him, we have our very being.
But there are different Graces. The Grace of the physical creation is different from the Grace of spiritual life (i.e., the rational soul), which is again different from the Grace of Divine Life, or the Grace of physical Immortality.
The Grace of physical life is shared by all of God’s creatures. This is called at times by the Fathers of the Church, the “animal” or “beast” nature.
The Grace of the rational soul is shared by all humans. In fact, it is the rational soul which makes us unique from the rest of God’s creatures. This is what the Fathers call, the “human” nature, which is the animal nature bonded to a rational soul. The rational soul is created and infused in the animal nature from the moment of each new human being’s creation (i.e., at conception). According to Fathers and the teaching of the Church, the rational soul is the form of the human nature, while the corruptible animal nature is the essence of the human nature.
NOTE: I’m not sure if there is a dogmatic Church teaching on whether God has a passive or active role in the creation/infusion of the rational soul (i.e., is the creation/infusion of the soul a natural faculty of humanity in the act of conception, or does God Himself directly create and infuse the soul at the moment of conception?).
Enter: the Grace of Divine life (i.e, [1] union with God and [2] Sanctifying Grace for our souls, which makes them perfect in the eyes of God) and the Grace of physical Immortality.
These Graces were present in the primordial state of man. Unlike the Grace of a physical life and a rational soul, they were not inherent in or natural to man, but was rather a gratuitous gift of God. Due to the sin of our first parents, these Graces were lost. What remained was/is our corruptible human nature. Thus, we experience both physical death, and spiritual death (i.e., separation from God)
Through Baptism in the Holy Spirit, our human nature can once again share in the Grace of Divine Life that was lost by our first parents. Our souls again become perfected in the eyes of God and can thus be in union with Him. But note that our souls do not become the essence of Grace, but rather, the Grace ACTS on our souls.
The seal of the Holy Spirit also promises us not just the Grace of physical immortality (likewise lost by our first parents) when Christ returns, but physical immortality itself. At the Resurrection, we will lose our corruptible animal nature (remember, human nature is the animal nature bonded to a rational soul). As St. Paul teaches us, we will be changed, shedding corruptibility and putting on incorruptibility.
At the Resurrection of the Dead, physical immortality will become our
natural state, whereas with Adam and Eve, it was still a gratuitous gift.
I confess that I am not sure if the Divine Life after the Resurrection of the Dead becomes natural to us as well, or remains a gratuitous gift of Grace. I am of the opinion that it will, like physical immortality, become natural to us.
I hope that helps.
Blessings,
Marduk