The foundation of the Christian spiritual life is Sanctifying Grace. As Sanctifying Grace is immaterial and thus not experienced directly, the Church’s theologians use various analogies to explain it. One of these analogies is made by comparing the relationship between Sanctifying Grace and the possessor’s soul to the relationship between the human soul and human body. This is because Sanctifying Grace does for the soul what the soul does for the body. In this sense, Sanctifying Grace can be seen as the supernatural soul of the soul.
In the first place, the soul is what specifies the material body, that is, it makes the matter to be the kind of thing it is, and not something else. The human soul is what makes a composition of matter to be a human body and not something else. In a similar way, Sanctifying Grace makes its possessor to be a specific type of thing, a supernatural organism.
The soul is the principle of natural life for the material body. Sanctifying Grace is the principle of supernatural life for the supernatural organism. The soul animates the body on the natural level. Sanctifying Grace animates its possessor with supernatural life and elevates him into a supernatural order of being.
Next, the soul is the principle of the various powers of the human person. All the powers one has –
augmentative, nutritive, generative, the senses, appetites, intellect, will – have their principle in the soul. In a similar way, Sanctifying Grace is the principle of “powers” (more properly habits) – the Infused Theological and Moral Virtues and the Gifts of the Holy Ghost – for the supernatural organism.
The soul is also the principle of unity for the material body. Even though individual organs and bones can be distinguished, and even individual cells, they are united into a whole which is greater than the sum of the parts. It is the soul which brings about this unity. In a similar way, Sanctifying Grace unites and orders the powers of the soul under the Infused Theological Virtue of Charity, which always accompanies Sanctifying Grace.
This understanding of Sanctifying Grace as the supernatural soul of the soul provides insight into the role
played by Sanctifying Grace in one’s own spiritual life and this knowledge should stir up in the possessor a greater love and appreciation for this great gift from God and for the Giver Himself.
