One of the most important concepts in Catholic theology, without which the Catholic faith will make very little sense to our students, is divine grace. Although the religion curriculums I worked with over the years certainly covered many important topics, I did not think they covered the subject of grace adequately, which to a certain degree would keep students from seeing the faith as a coherent and interrelated whole. What follows is a concise treatment of the fundamental idea of divine grace.
This topic begins with the distinction between nature and grace. To understand this more fully, consider that science is the study of the nature of things, i.e., the nature of inorganic substances (inorganic chemistry), or the nature of living things (biology), or the nature of the human person (psychology), etc. Philosophy too is the study of the nature of things, but philosophy pursues the "ultimate" nature of things, for it deals with questions that science cannot answer, questions that cannot be resolved empirically, but through reason alone, such as: "What is time?", or "What does it mean to be a human being?" or "What does it mean to exist?", or "What are the properties of being?", etc. In short, the object of human intelligence is the natures of material things.
The next point I'd like to stress is that we really only come to understand the nature of a thing through its activity. Hence, the nature of a living thing is essentially different from the nature of a non-living thing in that living things are capable of self-motion (i.e., growth, reproduction, and nutrition), while non-living things (such as a rock) are moved by virtue of an extrinsic cause (i.e., a person throwing the rock). Also, we know that both animals and plants are living, but animals are essentially different from plants in that animals are capable of an activity that plants are not capable of, namely sense perception. A rose bush cannot see or hear anything outside of itself, but a cat is able to see, smell, hear, taste, and touch things. Human beings, on the other hand, have much in common with plants and animals, for human beings grow, reproduce, eat and drink as plants do, and they see and hear things outside of themselves, but human beings are essentially different from animals and plants in so far as they can reason and make free choices-as opposed to being simply governed by instinct, as animals are. Hence, human nature is essentially different from canine nature, which is in turn different from feline nature, etc. There are a number of powers (faculties) that belong to human nature, two of which do not belong to the nature of a cat or dog or any other brute animal, namely intellect and will.
A power is really a potentiality to a specific activity. We infer the existence of these powers by observing the specific activity. For example, we infer that plants have the power to grow because we observe that plants actually grow (activity). We infer that the human person has the power to imagine, because the person imagines (activity); it is evident that many animals too have this power of imagination. Moreover, each of these powers or faculties has an immediate object. For example, the immediate object of the sense of sight is color, whereas the immediate object of the sense of hearing is sound, etc. The object of the imagination is the image, which is a material singular, such as the concrete image of an apple or triangle, etc., in the imagination. The object of the human intellect, on the other hand, is the universal idea, which exceeds the power of the imagination. For example, the idea of truth, or the concept of goodness, or the idea of "architecture", or the idea of "biology", etc., cannot be pictured in the imagination, and yet each of us knows what is meant by "biology", "architecture", "goodness" or "truth". But an idea or concept is not an image in the imagination; for what does the idea of truth look like? What color or shape is the idea of architecture? They don't have sensible qualities; ideas don't look like anything, for they are not sensible, rather, they are intelligible.[1]
Our knowledge begins with sensation, and following upon sense perception is sense appetite, for example the desire for the apple we perceive. Our knowledge, however, is not limited to sense perception, nor are our appetites limited to sense appetites - there is also an intellectual appetite (the will). Intellectual knowledge exceeds the limits of sense perception, and so the will (intellectual appetite) is a different power than the sense appetites; for example, although I desire to eat a tasty meal (sense appetite), I can choose to fast for 12 hours or more for the sake of a blood test. In this case, my sense appetite inclines me to eat, but my will can rise above that sense appetite so that I actually will (intend) to fast for health reasons.
Human nature, however, is limited. We can only know the natures of material things; for our knowledge begins with sensation and observation of a thing's activity. It is true, however, that we can reason to the existence of a being that we cannot perceive, a being that is not material, namely God.[2] However, we cannot know the nature of God directly and immediately, as we know material things. We can know, through reason, that there exists an absolutely first cause of all that has existence, that such a being is the Necessary Being that cannot not exist, that always existed, and is unchanging and eternal, supremely good, etc., but we cannot directly know the nature of God-for we only know the natures of material substances, and that knowledge, as we said above, begins with sense perception and observation of their activities, and God is not a material substance that can be perceived and observed. Indeed, it is truly exhilarating to reason to the existence of a first existential cause, but the knowledge we are left with is very abstract and indirect.
The bottom line is that the divine nature is beyond the capacity of the human mind to apprehend; all we can know naturally are material substances. Now, it is true that we have a natural and preconscious knowledge of God, which is the reason why we are forever searching for the causes of things and why we desire perfect happiness, but demonstrating that we have this knowledge is not easy, and this natural but preconscious knowledge of God is just that, natural, not supernatural, and very limited.[3]
The only way the human person can know God directly and immediately, that is, to know something of God that exceeds his natural limits, is through the power of the divine nature itself. God must grant the human person a share in his divine nature, thereby elevating the human being so that he or she becomes more than human without ceasing to be human. Only then are we able to believe what God has revealed about himself, for what he has revealed about himself will "ring true", for it will be congruent with something within us. And this is precisely what divine grace is: a sharing in the divine nature.
Consider the following analogy. You have a dog, which has a canine nature with very specific powers, i.e., five external senses, internal sensation such as instinct, imagination, sense memory, etc., as well as sense appetites, such as desire, aversion, pleasure, sorrow, anger, hope, daring, etc. Imagine you had the power to infuse your human life into your dog, so that the dog becomes more than canine without ceasing to be canine-hence, your dog, participating in your human nature, is both canine and human simultaneously. Your dog would then have certain capacities that it otherwise would not possess, powers that exceed the limits of canine nature, such as the capacity to possess universal ideas, carry on a conversation with you, and choose an intelligible course of action (fast for 24 hours). This of course is pure fiction, but this is what happens with divine grace. God infuses his divine life into the soul, granting it a sharing in the divine nature. The result is "deification", as the Greek fathers would say. A human being in a state of grace is more than human without ceasing to be human.
By virtue of that union between human nature and divine grace, the human person has capacities that exceed the limits of human nature. For example, God knows himself naturally, and so with the infusion of divine grace, which is a participation in the divine nature, the human person knows God with the very knowledge of God himself (the divine light), that is, he or she knows God supernaturally. Of course, this supernatural knowledge is not the fullness of the divine light, but is analogous to the light of the sun at dawn-although one cannot see the sun yet, one can see the rays of sunlight on the horizon as the sun slowly begins to rise. The light of those rays is the same as the light of the sun that is still hidden but rising. Similarly, the light that results from the state of grace is the very same light of glory that will enable the human being to see God as he is in himself, in the beatific vision. This light is the theological virtue of faith - the saints, such as St. Catherine of Siena, speak of the light of faith. Faith is a theological virtue, not a natural virtue. What this means is that one cannot give oneself faith; it is a gift. Although a person can cultivate natural virtues such as patience, honesty, or temperance, one cannot cultivate the supernatural virtue of faith. That is a gift, a grace. One must possess a degree of divine light in order to genuinely believe truths that exceed the capacity of human reason to determine, such as: God is Father, Son, and Holy Spirit, three Persons in one divine nature, or that Jesus is the incarnation of God the Son and that he came to save us from eternal death, that his death on the cross reconciles humanity to God, that he rose from the dead on Easter Sunday, that through baptism we enter into his death and rise to the new life of grace, that in consuming the Eucharist, we consume his body, blood, soul and divinity, not symbolically but really and truly, etc. That light of faith exceeds the limits of natural human knowing; the knowledge that faith imparts is dark and obscure, but it is a real sharing in the divine self-knowledge and thus has to be freely given by God. Similarly, grace imparts a certain hopeful confidence in God and his promises, such as "...everyone who looks to the Son and believes in him shall have eternal life, and I will raise him up at the last day" (Jn 6, 40). This is a real hope that is grounded in that dark but supernatural knowledge that is the light of faith. And finally, God loves what he knows, namely himself, and so a sharing in the divine nature includes a sharing in that supernatural love of God, which is the theological virtue of charity.
Now, activity implies power, for example, if I am thinking, then I have the power to think. A power that belongs to the nature of a thing is a faculty (i.e., intellectual activity in man implies an intellectual faculty, which in turn belongs to the nature of the human person). So too, the supernatural activities of faith in what God has revealed about himself and hope in the promises that God has made in his historical relationship with Israel as well as in the Person of Christ, and the intimate love and friendship of God, imply supernatural faculties rooted in "supernature".
The more we think about grace, the more we realize how very mysterious it is. For example, we cannot procure grace on our own power; it is given gratuitously, without our having earned it; to earn grace would require that one perform a supernatural act that has supernatural merit, but one must be elevated by grace first in order to perform such an act. However, God does not compel. Grace saves, but we are not saved without our consent, that is, without our cooperation. However, my free cooperation with the movement of God's grace is itself a grace. Although I cannot do anything to earn grace, I am capable of rejecting the impetus of divine grace. This means that if I make it to heaven, it is by virtue of God's grace; if I do not make it to heaven, it is as a result of my own choosing, my own refusal to cooperate with the movement of grace.
Sanctifying grace is the state of grace; it is habitual. A habit is an enduring quality, an enduring disposition. Thus, sanctifying grace is a habitual and interior state of supernature. But to get to this point, however, requires my cooperation, and yet I cannot cooperate without grace, as we said above. And so there must be a grace that precedes sanctifying grace, what the Church refers to as prevenient grace. Section 2001 of the Catholic Catechism puts it this way:
The preparation of man for the reception of grace is already a work of grace. This latter is needed to arouse and sustain our collaboration in justification through faith, and in sanctification through charity. God brings to completion in us what he has begun, "since he who completes his work by cooperating with our will began by working so that we might will it" (St. Augustine, De gratia et libero arbitrio, 17: PL 44, 901).
Another important point is the distinction between sanctifying grace and actual graces. Actual graces are divine interventions, or momentary helps that precede conversion or are offered throughout the course of one's spiritual life. These graces are a supernatural impetus that allows us to avoid sin or inspires us in some way; they could be a source of strength, or an illumination of some sort. Prevenient grace is an actual grace that is an impetus towards conversion, but it is not habitual grace. It is possible for the human person to shatter this divine impetus, sort of like a child that refuses to allow himself to be moved in a certain direction and so chooses to sit dead weight on the ground. Another term to become familiar with is sufficient grace. The latter is available to everyone, for it is a general term that refers to actual grace that is offered to everyone to a sufficient degree, that is, sufficient for a person to choose in a way that leads to the state of sanctifying grace.
Parents and children are always of the same nature. The divine nature, however, is infinitely different from human nature. It follows that human beings are not, by nature, related to God as a child is related to a parent. In other words, although human beings are creatures of God, created in the image of God (the image of mind and heart), they are not naturally "children" of God. Sanctifying grace, however, elevates human nature to participate in the divine nature; thus, sanctifying grace makes us sons and daughters, sharers in the sonship of Christ; for he referred to God as "Abba" (Father), for the Son is of the same nature as the Father (divine nature).
Furthermore, children possess a right of inheritance. Similarly, in a state of grace, there is a right to inheritance; what belongs to God becomes ours. To die in a state of grace is to die saved-we inherit eternal life. In a state of grace, one inherits supernatural gifts, namely, the gifts of the Holy Spirit-one shares to a certain degree in the divine wisdom, knowledge, and understanding. One also receives the gift of counsel, fortitude, piety, and fear. These gifts are a sharing in the sonship of Christ himself: "The spirit of the Lord shall rest upon him: a spirit of wisdom and of understanding, a spirit of counsel and of strength, a spirit of knowledge and of fear of the Lord, and his delight shall be the fear of the Lord" (Is 11, 2).
We also distinguish between mortal and venial sin. Mortal sin kills the grace of God within the soul, while venial sin only weakens the effects of divine grace in the soul. Grace, like fire, illuminates and exudes warmth, but venial sin dims that interior illumination, as a cover placed over a fire diminishes its light and warmth.
Although we cannot merit divine grace, a person in a state of grace can merit an increase in grace. Hence, the more one prays with faith, hope, and supernatural charity, and the more one engages in works of mercy rooted in that charity, etc., the more one merits an increase in grace. As we can see, however, this is a matter of cooperation with the movement of divine grace, which is itself a grace. In other words, no matter which way we look at it, no credit or glory is ours, but all is his. Section 2008 of the Catechism puts it this way:
The merit of man before God in the Christian life arises from the fact that God has freely chosen to associate man with the work of his grace. The fatherly action of God is first on his own initiative, and then follows man's free acting through his collaboration, so that the merit of good works is to be attributed in the first place to the grace of God, then to the faithful. Man's merit, moreover, itself is due to God, for his good actions proceed in Christ, from the predispositions and assistance given by the Holy Spirit.
Christ, who is the incarnation of the Second Person of the Trinity, is the source of grace for humanity. He is God the Son who joined a human nature, and in doing so, he has joined himself to every man and woman. This does not mean that everyone is in a state of sanctifying grace; that requires cooperation with sufficient grace, and not everyone cooperates, that is, not everyone allows Christ the king to reign within and have dominion over his or her life, but that is what we pray for in the Our Father: "...who art in heaven, may your name be made holy. May your kingdom come, may your will be done, on earth as it is in heaven". In Christ, heaven and earth are joined; hence, the kingdom of God is among us (Lk 17, 21), but we pray for the fullness of the kingdom, when God will be "all in all" (1 Cor 15, 28).