From The Interior Life:
I. Perfect and imperfect life
This first part is entitled — THE END; the end is living, for man was made to live. And it is because I am made to live and this is my end, that it is useful to put at the head of this first part a preliminary section, entitled—Life.
And what is living? It is having within one an activity of one’s own, arising from an inward principle, which is capable of developing itself by its own action and of possessing its own development.
There are two kinds of life: perfect and imperfect. The perfect life is that which belongs to a being which is self-possessed and finds its exercise in the fulness of a movement which leaves nothing to be achieved. The absolute fulness of such life is to be found in God alone. The divine act whereby God possesses, knows, and loves Himself in the Trinity of the divine Persons is an infinite act, and this act is the life of God in Himself.
In heaven, I shall have the fulness of life of which my being has become capable, and I shall possess eternally and changelessly, in one act wherein my whole vital powers will find their exercise, the development which I have acquired. This will be, in my own measure and degree, perfect life.
Here below life is imperfect. And what is imperfect life? It is the movement of acquisition whereby a being is developed. The internal principle of activity goes on increasing and expanding by its own action. It is a life which forms and builds and organizes itself. The characteristic signs of this life are acquisition and growth. The growth of an imperfect being is an essential manifestation of its life. And such is the condition of my present life.
II. Natural and supernatural life
I am made to live. What does this mean? It means that I am called to develop in myself the fruits of holiness in this world, in order to gain in heaven, as an end, and without end, eternal life. The life of this world is growth, the life of heaven is possession, and both are the proper activity of my being.
I have my soul and my body; my soul is itself living a life imparted to it by God; my body is living by my soul, which imparts animation thereto. My soul can act, and it acts by means of the faculties which appertain to it. My body can act, and it acts by means of the powers which belong to it, and which are animated and controlled by the soul. The soul has a complete organization of knowing, willing, and acting faculties, and the body has a whole series of organs attached to the faculties of the soul and acting by them. And it is in the action of these faculties and powers that my natural life consists.
By God’s grace I have another life, i.e., another capacity for action which no longer depends upon me, but upon God. This is the supernatural life, whereby God, uniting ineffably with my nature, raises me above myself and imparts to my faculties the power of doing divine acts. Thus He Himself becomes the life of my life, the soul of my soul: a mystery of love! And this life is supernatural life, i.e., eternal life; it is the development on earth of the life I shall enjoy in heaven.
Note: Some of the above may seem dry to modern readers, but it is our foundation, our grasp of the basic elements of our existence and the purpose thereof, that stands in need of assistance. No, this is not true in every single case, but it is more common than we recognize or would like to admit. If our foundation is weak or imperfect, so will be the structure we build upon it.
When seeking to understand these matters and grow in the life of grace and love, it is paramount that we grasp the distinction between the natural and supernatural orders. Sadly, this vital distinction has been all but obliterated in the minds of modern men; all sorts of confusion has followed as a result.
All of creation, whether visible or invisible, composes the natural order. The angelic nature, in itself, is above our own, but it is not supernatural, properly speaking. A fallen angel is superior to men from the viewpoint of nature, but a man living the supernatural life is above all fallen angels from the viewpoint of grace. When an intelligent creature possesses the supernatural life, this means said creature possesses God’s own infinite life, albeit by means of a finite participation.
While it is possible for us to be elevated to a participation in God’s own supernatural life, such is neither automatic nor part of our nature — and, contrary to the ideas of some, we can deprive ourselves of this great gift after it is acquired if we fail to be faithful to grace and the will of God. Some never acquire this supernatural life during the course of their natural life. God provides ample opportunity to all, but some choose not to accept the gift that God offers.