It appears that many theologians today either do not have a clear understanding of the metaphysics of participation (leaving that up to the philosophers) or do not see the importance of participation with regard to the bearing that it has on theology, particularly within the realm of Christology and grace. This is unfortunate, because without an understanding of sanctifying grace as an ontological participation in the life of God, Christians are left with the idea of justification as a simple “covering over” of sin,Footnote 1 without any real transformation taking place in the soul. Nevertheless, as we will see, the notion of participation is actually operative throughout the thought of St. Thomas and within the Catholic understanding of the creature's relationship to God—in particular, with regard to sanctifying grace.
Analogy of Being
Before speaking any further about participation, however, it is important to understand something of St. Thomas’ view of analogy with regard to being, and consequently, with regard to the transcendentals, and to the supernatural life of grace, as well.
In his Commentary on Aristotle's Metaphysics, Aquinas clearly illustrates the three principal ways in which one thing can be predicated of another: univocally, equivocally and analogously. In explaining the first two ways, he states:
In the case of univocity one term is predicated of different things with absolutely one and the same meaning; for example, the term animal, which is predicated of a horse and of an ox, signifies a living, sensory substance. In the case of equivocity the same term is predicated of various things with an entirely different meaning. This is clear in the case of the term dog, inasmuch as it is predicated both of a constellation and of a certain species of animal.Footnote 2
Before beginning his explanation of the third mode of predication, i.e. by way of analogy, Aquinas refers to Aristotle's example of the term, “healthy”, which, St. Thomas says, can refer both to one thing, such as urine, which is a sign of health, and to another thing, such as medicine, which causes health:
But…[when] the same term is predicated of various things with a meaning that is partly the same and partly different—different regarding the different modes of relation, and the same regarding that to which it is related; for to be a sign of something and to be the cause of something are different, but health is one. Terms of this kind, then, are predicated analogously, because they have a proportion to one thing.Footnote 3
Aquinas then goes on to explain that the same holds true with regard to “being” (ens), which, simply speaking, can refer to a substance (“that which has being [i.e. esse] in itself”), but in a less proper way can also refer to an accident, which “belongs to” that which has being through itself, i.e. that which inheres in the substance.
But what about with regard to God Himself? How do we predicate “being” both of God and of a creature? First of all, Aquinas points out in De Veritate that nothing can be predicated univocally of God and a creature, because, he explains,
…for in all univocal things, the definition of a name is common to both of those things concerning which the name is univocally predicated; and thus as pertains to the definition of that name, univocal things are equal in some way (although according to being, one thing may be prior or posterior to another).…Footnote 4
Here Aquinas gives the example of numbers, which all have the nature of a number, even though one may be naturally prior or posterior to another. However, as Aquinas points out, no matter how much a creature may imitate God, it will never reach a point in which something may belong both to it and to God in the same respect. That is, in the case of creatures, it is possible for them to share a certain formality with regard to substance or essence, though they are distinct with regard to being, but God is His own Act of Being and His essence is the same as His Act of Being. Therefore, just as one creature cannot communicate his own act of being to another, likewise it is impossible for a creature to possess some attribute in the same way that God possesses it.
Nevertheless, says Thomas, this does not mean that a creature is doomed to a purely equivocal predication with regard to itself and God, otherwise we could not say that there was any real likeness of God in creatures at all, and we would not be able to attain to any real knowledge of God from His effects. Therefore, there are some attributes which can be predicated analogously of God and creatures, though they must be, as Aquinas explains, “all things in whose definition is not included a defect, nor [things which] depend on matter for being [esse], such as being [ens], good, and other things of this sort.”Footnote 5
A Metaphysical Notion of Participation
Fr. Cornelio Fabro, an Italian Thomistic philosopher, points out that “participation” can have multiple senses. It can refer to a participation in the quantitative and material order, as in participating in a pizza, in which the “whole” is divided and distributed in parts (resulting, however, in a diminishing of the whole as pieces are taken from the pizza, for example), or it can refer to a metaphysical notion of participation, which “concerns properly speaking the mode of having and receiving, in the sense that the ‘whole’ remains intact and undivided, while an aspect or form of the object is being participated.”Footnote 6 This would be the case, for example, in which one participates in “goodness” or “whiteness”, without causing any diminishment to the forms of “goodness” or “whiteness” as a result.
Let us begin with a basic understanding, then, of the etymological explanation Aquinas gives of participation. Aquinas clearly defines participare in De hebdomadibus, where he says, “To participate is, as it were, to take part, and therefore, when something receives partially that which belongs to another universally, it is said to participate in that, just as man is said to participate in animal, because he does not have the notion of animal according to the whole commonality.”Footnote 7 In other words, to participate in something is to have a share in it in some way, as in the case of the essence of man, who is, according to Aristotle, a “rational animal”, whereby man participates in the genus of “animal”, without containing in himself the totality of all animality (since other creatures are also said to belong to this genus).
However, it is important to note here that in speaking of participation in genus and species, St. Thomas is not adopting a Platonic view that the genus or species have a real existence separate from those that participate in them. With regard to any ontological content, one must say with Fabro that the genus and species
are present in their respective subjects and must therefore be predicated essentially [i.e. as part of the definition]… and not by participation…. [However,] With regard to the mode of being (and therefore the mode of being actualized in a concrete reality) a genus is differently actualized in the various species according to different degrees of perfection….Thus participation involves no doubt a univocal nature or essence but only insofar as this is raised to a metaphysical level and considered as a “whole”, that is, as a complex of virtual perfections that are being divided into or participated by the various species (for the genus) and the many individuals (for the species)….Footnote 8
Aquinas explains further what he means by participation in his Commentary on the Metaphysics of Aristotle. He writes, “For that which is something in its entirety does not participate in it but is essentially identical with it, whereas that which is not something in its entirety but has this other thing joined to it, is said properly to participate in that thing.”Footnote 9 He then proceeds to give the example of heat, “which if it were heat existing through itself, would not be said to participate in heat, because nothing would be in it but heat,”Footnote 10 whereas fire, because it is something other than heat, can be said to participate in heat. In other words, participation for St. Thomas means to have an act or formality in a limited, imperfect, particular way, which is received from one who has it in an unlimited, perfect and universal way.
In De hebdomadibus, Aquinas presents three types of participation, the first two of which were mentioned above: 1) logical / notional participation, i.e., a species participates in a genus, and an individual in a species (as in our first example of man participating in the genus of animal); 2) a real participation, i.e. a substance participates in an accident, and matter in a form (as in our second example of fire participating in heat); and finally, 3) a causal participation, i.e. the effect participates in its own cause.Footnote 11
Without getting into the various types of causes, it is important to emphasize this relationship between participation and causality. As Aquinas points out, “Whatever is found in anything by participation, must be caused in it by that to which it belongs essentially…”Footnote 12 Then, after noting that God is Ipsum Esse per se subsistens, Aquinas adds, “Therefore all beings apart from God are not their own being, but are beings by participation. Therefore it must be that all things which are diversified by the diverse participation in being,… are caused by one First Being, Who possesses being most perfectly.”Footnote 13 Here we begin to understand something of Divine Causality as the source of participation.
Fr. Cornelio Fabro also distinguishes another type of grouping of participation in St. Thomas, which he terms predicamentale‐univoco and trascendentale‐analogo.Footnote 14 He explains that in the univocal‐predicamental participation, “All the participants have in themselves the same formality as to the whole of its essential content, and the participated thing does not exist in itself, but only in the participants.”Footnote 15 For example, “humanity” does not exist outside of the human beings in which it is found univocally.
However, in the case of analogous‐transcendental participation, Fabro points out that “the participants have in themselves only a ‘down‐graded likeness’ of the participated thing which subsists in itself, outside of these, either as a property of a superior subsistent, or certainly, as a pure and subsistent formality in full possession of itself.”Footnote 16 This is the most intense meaning of participation, already found in Plato, and taken up by St. Thomas. This analogous participation, says Fabro, “…is that of the creature from the Creator which, being esse by essence, sums up in Himself all the other perfections, formally if they are pure perfections, virtually if mixed.”Footnote 17
It is important to recognize the existence of this analogous participation in order to maintain the transcendence of God. Creatures do not share being with God in a univocal way, nor in a completely equivocal manner. As Cavanaugh points out,
For Aquinas… it is the rejection of the univocity of being that allows the participation of the human in the divine. For precisely because God is entirely transcendent to creaturely being, because God is not another being in competition with finite being, God is the only agent who acts immediately—that is, through no medium—in all things
(I.8.1, ad 3).Footnote 18According to Fabro, causality can be understood as predicamental participation (“concerned with fieri, which is the becoming or development of created reality within the order of genera and species”) or transcendental participation (which “extends to both creation and conservation, to form as well as to matter”).Footnote 19 In this latter sense, “the form is the true cause of esse, but only within its order, inasmuch as it is the predicamental mediator between created finite being and the esse per essentiam, which is the First Cause.”Footnote 20
Participation in Being and Image
It is important to note that Aquinas understands participation within the Aristotelian framework of act and potency. In the Summa, Aquinas explains, “Everything participated is compared to the participator as its act.”Footnote 21 The Angelic Doctor goes on to explain that every created form must participate in esse, but one's degree of participation is limited by the capacity of the one participating. Whence, he says, “…only God, who is His own esse itself, is pure and infinite act,”Footnote 22 whereas the intellectual substances (and the rest of creation) are limited in esse according to their capacities to receive it, i.e., they are a composition of act and potency, participating in that esse. Rziha notes, “Thus, in Thomistic thought, participation is a sharing in the essential act of another, which is limited by the potency of the participating subject.”Footnote 23
In Thomas’ understanding of participation within this Aristotelian framework, Rziha points out that act is to be understood as a perfection. He explains, “Humans are perfected by that act of esse that takes part in the esse of God. Yet even here Thomas goes beyond Aristotle by seeing potency as the capacity to receive perfection and seeing act as the perfection of esse.”Footnote 24 Therefore, for Aquinas, the essence of a corporeal creature, although composed of matter and form (which functions as potency to act) is itself also related to esse as potency to act. This holds true for non‐corporeal creatures, as well, which participate in esse (and are not their own esse), and so must be said to be composed of potency and act even though they contain no matter.Footnote 25
Therefore, all creatures participate in God's esse, “…because God is called a Being [ens] in this way, that He is His own being [esse] itself; a creature, however, is not its own being [esse] itself, but is called a being [ens] as participating in being [esse].”Footnote 26 As Fabro notes, a formality can exist and be predicated either per essenza or per partecipazione.Footnote 27 God, of course, is His own Esse by essence, whereas creatures only receive esse by participation.
Here, however, we should note the distinction between esse commune and the Divine esse. As Wippel explains, for St. Thomas, the esse commune “is that intrinsic principle, that act of being, found in every existing entity, that is, every substance, which accounts for the fact that it actually exists.”Footnote 28 In other words, all creatures depend on the esse commune for their existence, whereas the esse commune (i.e., created being) depends on God (Uncreated Subsistent Being Itself) as its cause and principle. Wippel notes, “In participating in the esse which is efficiently communicated to it by God, the creature may also be said to participate in some way in God, that is, in his likeness.”Footnote 29
However, Aquinas indicates that man shares in a certain likeness to God which is different from that of irrational creatures. He explains:
The likeness of image is found in human nature, forasmuch as it is capable of God [capax Dei]—viz., by attaining to Him through its own operation of knowledge and love. But the likeness of trace regards only a representation of the Divine impression, existing in the creature, and does not imply that the irrational creature, in which such a likeness is, can attain to God by its own operation alone.Footnote 30
Cessario describes the three stages of this image as found in man, known as the “imago Dei.”Footnote 31 The first stage is that of the Natural Image, by which man loves God in the natural order “inasmuch as He is the beginning and the end of natural good,”Footnote 32 without the help of sanctifying grace. Man alone has, as St. Thomas puts it, a certain natural capacity for God, because man is created with an openness and potential to attaining to universal truths and to universal goods, taken distributively, and is thereby rendered capable of being elevated to God (the Universal True and the Universal Good par excellence) by means of grace.
Now the created rational nature alone is immediately subordinate to God, since other creatures do not attain to the universal, but only to something particular, while they partake of the Divine Goodness either in “being” only as inanimate things, or also in “living”, and in “knowing singulars”, as plants and animals; whereas the rational nature, in as much as it apprehends the universal notion of good and being, is immediately related to the universal principle of being. Consequently the perfection of the rational creature consists not only in what belongs to it in respect of its nature, but also in that which it acquires through a supernatural participation of Divine goodness.Footnote 33
This leads us to the second stage, the Image of Grace, also known as the imago Christi, which is a supernatural participation in God's goodness and nature that comes to us through Christ.
However, we should first note that man already has a certain natural participation in goodness, because in participating in God's esse, man also participates in the other transcendentals which are convertible with being and transcend all particular categories of being, being common to all of them. Goodness is one of the commonly‐listed transcendentals, along with truth and oneness. Aquinas explains in De Veritate, “In this way an essence is called good, inasmuch as it is a being [ens]; whence just as it has being [esse] by participation, thus it is also good by participation.”Footnote 34 In other words, just as God is Esse essentialiter, because only God is subsistent esse, whereas being must be predicated of creatures per participationem, “so also God is called good essentially, because He is goodness itself; however, creatures are called good by participation, because they have goodness….”Footnote 35
Nonetheless, it is the supernatural “participation of the Divine goodness” that is grace,Footnote 36 which in turn, prepares the soul for its final conformity to God in beatitude, known as the Image of Glory. Here one should point out that for Aquinas, there are two modes of participation in the divine light, of which faith is the imperfect, yet prior participation, and the vision of glory is the perfect participation.Footnote 37 Fabro notes:
The proper and full vision will occur only when, after this life, to whomever dies in grace, will be communicated the light of glory which is, in a certain way, the most proper participation in the vitality itself of God, whence the creature enters into communion with the very object of which God Himself lives. The participation of the “lumen gloriae” tends to complete in an ineffable way this assimilation of the created intellect….Footnote 38
The Image of Glory, therefore, is the highest form of participation possible to a creature, other than that of the hypostatic union itself. In his writings on the Sentences, St. Thomas points out that the “last and most complete participation in His [i.e. God's] goodness consists in the essential vision of Him [i.e. the Beatific Vision], by which we live together with Him socially as friends, since in that… beatitude consists.”Footnote 39
In participating in the Beatific Vision, Aquinas notes that man will participate in eternity itself, “the simultaneously‐whole and perfect possession of unending life,”Footnote 40 since in the vision, “all things that are seen through it are seen at once, and in one view.”Footnote 41 This participation in eternity consists in a certain unchangeableness in being and operation for those who share in God's eternal life.Footnote 42
We can sum up these three stages or images in man, therefore, with an explanation from Aquinas:
Wherefore we see that the image of God is in man in three ways. First, inasmuch as man possesses a natural aptitude for understanding and loving God; and this aptitude consists in the very nature of the mind, which is common to all men. Secondly, inasmuch as man actually and habitually knows and loves God, though imperfectly; and this image consists in the conformity of grace. Thirdly, inasmuch as man knows and loves God perfectly; and this image consists in the likeness of glory.Footnote 43
Christ as Head
Fabro points out that when St. Thomas answers the question of whether the lack of original justice gives rise to the notion of guilt in Adam's descendants, he explains original sin as a sin of nature, by using the concept which Fabro refers to as “predicamental participation.”Footnote 44 Aquinas states:
This question is easily solved if we but distinguish between person and nature. As there are many members in one person, so there are many persons in one human nature. Thus, by sharing in the same species, many men may be thought of as one man, as Porphyry remarks… In this way, then, the privation of original justice is a sin of nature, in the sense that it has its origin in the inordinate will of the first principle in human nature, namely, of the first parent. Thus it is voluntary with respect to nature, that is, by the will of the first principle of nature. And so it is transmitted to all who receive human nature from him, for they are all, as it were, his members.Footnote 45
In a similar way, Aquinas uses the idea of predicamental participation in speaking of how Christ could merit for others. He explains that Christ is the Head of the Church, and even goes so far as to say “Christ and the Church are as one person,”Footnote 46 and he later adds, “Christ could therefore merit for the faithful as for His own members….”Footnote 47 Likewise, in speaking of the efficiency of Christ's passion, Aquinas notes:
Grace was bestowed upon Christ, not only as an individual, but inasmuch as He is the Head of the Church, so that it might overflow into His members; and therefore Christ's works are referred to Himself and to His members in the same way as the works of any other man in a state of grace are referred to himself.”Footnote 48
In fact, Fabro points out that the Incarnation began a new stage in the economy of salvation. Whereas the good angels and our First Parents participated in the gratia Dei (i.e., grace directly from God, given before the Fall),
…the grace of the regenerated men, rather, is participated through Christ, who has merited it. This is, therefore, the “gratia Christi”, and all the gifts which God now effuses into the holy souls are a participation in the fullness of the gifts which is in Him. Christ, therefore, comes to be considered like a new font of supernatural participations.Footnote 49
However, predicamental participation can only explain the mode of our participation in grace, i.e., through Christ, and not what grace is in itself, which, as Aquinas notes, “is nothing short of a partaking in the Divine Nature.”Footnote 50 Participation in the divine esse, as we have said, is an analogous‐transcendental participation, and in this way, grace is a new creation. Therefore, it would appear that the grace of the Holy Spirit which we receive through Christ is an analogous‐transcendental participation in God's own life, but it remains a sort of predicamental participation in the way that we receive it, which is by being united to Christ as members of His Mystical Body.
However, we must not understand this to mean that Christ Himself is merely a participant in God's life. In fact, the head or source of a perfection does not itself participate in the perfection of the genus, because it is the cause of that perfection. Aquinas explains:
So that has life in itself which has an essential, non‐participated life, i.e., that which is itself life. Now in every genus of things, that which is something through its essence is the cause of those things that are it by participation, as fire is the cause of all things afire. And so, that which is life through its essence, is the cause and principle of all life in living things. Accordingly, if something is to be a principle of life, it must be life through its essence. And so our Lord fittingly shows that he is the principle of all life by saying that he has life in himself, i.e., through his essence, when he says: just as the Father possesses life in himself, i.e., as he is living through his essence, so does the Son.Footnote 51
Therefore, the primary source of all participation in the life of grace is Christ, as Head of the Church. Nevertheless, Aquinas also observes that “…the soul of Christ is not Divine by its essence. Whence it is necessary that it be made Divine by participation, which is according to grace.”Footnote 52 Consequently, although in the Person of the Word, Christ is the natural Son of God, His humanity needed to “attain to God by a created act of fruition which indeed cannot be except by grace.”Footnote 53 In other words, in order for Christ, in his human operation, to cooperate with the Divine operation, it was necessary for Christ to have habitual grace.
Participation in the Grace of Christ
In the hypostatic union, Christ's human nature is made to participate in the life of the Divine Person of the Son, with the result that, as Fabro explains, “This [union] has become the primary source of all participation in grace by believers inasmuch as the human nature of Christ is the close instrument of the divinity.”Footnote 54 This is important, because, as Aquinas notes, “…therefore His actions could be salutary for us.”Footnote 55 In other words, Christ's humanity serves as an instrumental cause, moved by the principle agent of His Divinity:
The Divine Nature makes use of the operation of the human nature, as of the operation of its instrument; and similarly, the human nature participates in the operation of the Divine nature, just as an instrument participates in the operation of the principle agent.Footnote 56
St. Thomas also notes that the personal grace by which the soul of Christ was justified is essentially the same as the grace by which He is the Head of the Church, allowing for a distinction of reason. He observes, “…in the soul of Christ, grace was received in the highest way. And therefore, from that pre‐eminence of grace which He received, it belongs to Him that grace is bestowed on others, which pertains to the nature of Head.”Footnote 57
It is important to note that the first and most important way in which we can participate in Christ is by means of divine sonship.Footnote 58 Christ is the natural Son of God by the grace of union, and we are called to participate in that divine filiation, and so become the adopted sons of God by means of habitual grace, which is both created and an accident in us. As Aquinas states, “…the sonship of adoption is a participated likeness of natural sonship….”Footnote 59
In other words, Christ, as Perfect God and Perfect Man, has become the mediator uniting us to God, “by communicating to men both precepts and gifts, and by offering satisfaction and prayers to God for men.”Footnote 60 The principle gift given to men is grace, which is chiefly bestowed on us through the sacraments. The Angelic Doctor explains:
As in the person of Christ the humanity causes our salvation by grace, the Divine power being the principal agent, so likewise in the sacraments of the New Law, which are derived from Christ, grace is instrumentally caused by the sacraments, and principally by the power of the Holy Ghost working in the sacraments….Footnote 61
It is through the sacraments, of course, that the soul participates in the divine sonship, with the sacrament of Baptism being “the gateway to life in the Spirit (vitae spiritualis ianua), and the door which gives access to the other sacraments.”Footnote 62 Baptism, then, is the primary source of grace, which, “in the very essence of the soul by means of a kind of indwelling, is the root and cause of infused virtue.”Footnote 63 In fact, the theological, as indeed all the infused virtues, are given to the soul at baptism, and not only are original and personal sin removed from the soul, but the person is also incorporated into the Mystical Body of Christ, which incorporation allows each one to participate in the grace of Christ as if it were his own.
However, Aquinas is careful to distinguish the instrumental agency of the sacraments from that of Christ's humanity, explaining that an instrument can either be united (as one's hand is united to the body) or separate (as a stick, for example). The separate instrument is always moved by the principal agent by means of the united instrument. Therefore, St. Thomas is able to explain the causality of the sacraments:
Now the principal efficient cause of grace is God Himself, in comparison with Whom Christ's humanity is as a united instrument, whereas the sacrament is as a separate instrument. Consequently, the saving power must needs be derived by the sacraments from Christ's Godhead through His humanity.Footnote 64
Yet one might ask what makes the sacraments so efficacious. Aquinas points out that it is Christ's Passion. He explains, for example, “The heavens were opened at Christ's baptism, not for Christ's sake, to whom heaven was ever open, but in order to signify that heaven is opened to the baptized, through Christ's baptism, which has its efficacy from His Passion.”Footnote 65 In another place, speaking of Christ's Passion as the “universal cause for the forgiveness of sins,”Footnote 66 Aquinas adds that “this is done by baptism and penance and the other sacraments, which derive their power from Christ's Passion….”Footnote 67
Of course, the sacraments do not come to us without the Church which Christ founded. The Mystical Body of Christ is not a merely invisible incorporation, but involves a visible community, which often comes together to participate in the grace given through the various sacraments. As Levering points out, “For Aquinas, in short, the sacraments create a visible community whose purpose it is to mediate participation in Christ's passion.”Footnote 68
Justification by Grace
The Council of Trent, in speaking of the causes of our justification, explains that the meritorious cause is Christ, who “merited for us justification by his most holy Passion on the wood of the Cross [can. 10] and made satisfaction for us to God the Father.”Footnote 69 The Council then goes on to name baptism as the instrumental cause. Therefore, Christ has merited the First Grace of justification for us, inasmuch as we participate in His Passion (particularly in baptism, in which we “die with Christ”—cf. Rm 6:8), but we are also able to merit future graces in union with Christ. Levering explains, “Cooperating with grace, we become just through the works that grace enables us to perform. The source of our justification, ultimately, is not our own works but Christ's meritorious justice, which we share in by grace.”Footnote 70 In fact, the Council of Trent declares that we are justified by the justice of God, in the sense that He makes us formally just, spiritually renewing us:
…not only are we considered just, but we are truly called just and we are just [cf. 1 Jn 3:1], each one receiving within himself his own justice, according to the measure that “the Holy Spirit apportions to each one individually as he wills” [cf. 1 Cor 12:11] and according to each one's personal disposition and cooperation.Footnote 71
In other words, Catholics believe that the justification of Christ is not a merely outward imputation of justice, but a true, inward inherence of the grace of justification in the soul, which renews and sanctifies it by making it participate in God's own life. In speaking of grace as the principal effect of the sacraments, Aquinas cites the second letter of St. Peter which states:
His divine power has granted to us all things that pertain to life and godliness, through the knowledge of him who called us to his own glory and excellence, by which he has granted to us his precious and very great promises, that through these you may escape from the corruption that is in the world because of passion, and become partakers of the divine nature.Footnote 72
Aquinas explains that Christ's suffering and death not only delivers us from original sin, but also “from the personal sins of individuals who share in His Passion by faith and charity and the sacraments of faith.”Footnote 73 It is the theological virtue of charity, in particular, which inspired the saints to desire to participate in Christ's Passion and through which grace is the principle of meritFootnote 74 for us. In fact, our love for God and neighbor is itself a participation in the Divine charity:
Wherefore just as we are said to be good with the goodness which is God, and wise with the wisdom which is God (since the goodness whereby we are formally good is a participation of Divine goodness, and the wisdom whereby we are formally wise, is a share of Divine wisdom), so too, the charity whereby formally we love our neighbor is a participation of Divine charity.Footnote 75
Of course, the Eucharist is the ultimate sacrament of charity, since by it, we not only participate directly in the sacrifice of Christ on the Cross, but we also receive Love Himself.Footnote 76 Aquinas explains the difference in the way one participates in Christ's Passion through the sacrament of the Eucharist versus that of baptism, saying:
Baptism is the sacrament of Christ's death and Passion, according as a man is born anew in Christ in virtue of His Passion; but the Eucharist is the sacrament of Christ's Passion according as a man is made perfect in union with Christ Who suffered. Hence, as Baptism is called the sacrament of Faith, which is the foundation of the spiritual life, so the Eucharist is termed the sacrament of Charity, which is the bond of perfection….Footnote 77
It is, indeed, in the holy sacrifice of the Mass where the members of the Mystical Body of Christ participate most fully in Christ's saving Passion here on earth, which is at the same time a foreshadowing of and an already real participation in the heavenly liturgy.Footnote 78 Aquinas points out that the Eucharistic celebration is “a certain image representative of Christ's Passion, which is a true immolation,”Footnote 79 and the Mass is called a sacrifice “with respect to the effect of His Passion: because, namely, by this sacrament, we are made participants of the fruit of the Lord's Passion.”Footnote 80
So, then, this sacrament benefits recipients by way both of sacrament and of sacrifice, because it is offered for all who partake of it. For it is said in the Canon of the Mass: May as many of us as, by participation at this Altar, shall receive the most sacred body and blood of Thy Son, be filled with all heavenly benediction and grace.Footnote 81
Conclusion
Esse may be predicated only analogously of God and creatures. Creatures, which have being by participation, receive their being from God, who is Being by essence. Distinct from all irrational creatures, man is created in the image and likeness of God, which involves a natural participation in God's esse, in which man is made capax Dei, because his intellect is ordained to universal truths and his will to universal goods, so that he is capable of being elevated, unlike other corporeal creatures, to a supernatural participation in God's goodness, which comes to him through Christ. In fact, Christ Himself becomes the source of grace through the participation of His Humanity in the power of His Divinity, and through our participation in Him as members of a body participate in the Head.
The highest form of participation possible to us is the Beatific Vision. In order to attain to this glory, however, we are called to first participate in divine sonship and in the gifts of virtue and grace which come to us through the sacraments and which are celebrated within the visible community of the Church. The power of the sacraments and the possibility of justification and merit are only made possible through a certain participation in the Passion of Christ, informed by the theological virtue of Charity.
In summary, therefore, it is important to note the significant role the metaphysical notion of participation has in Aquinas’ understanding, not only of creation, but also of the Incarnation and of the whole supernatural life of grace, justification and merit. We have said that grace can be understood as an analogous‐transcendental participation in God's own life which is received as a predicamental participation with respect to Christ as members of His Mystical Body. But it is especially essential to the Catholic understanding of justification to have a proper conception of grace as a causal (and not merely moral) participation in the Divine Nature, and as something which inheres in the soul and really transforms it. Without this appreciation of the true value of grace in the soul, one can easily fall into an extrinsic, forensic view of justification, in which the soul always remains in a helpless state of sin.