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William E. May

Michael J. McGivney Professor of Moral Theology

John Paul II Institute for Studies on Marriage and Family at

The Catholic University of America

Washington, D.C., USA


            In her moral teaching the Church frequently appeals, and rightly so, to the universally binding principles and norms of the natural law. [1]Catholic faith holds that God himself has entrusted to the magisterium of the Church the awesome responsibility of authoritatively interpreting the natural law precisely in order to help men and women make good moral choices in the light of the truth.[2]The Church also teaches that the natural law — which is rooted in God's eternal, divine law [3] — is fulfilled and perfected by the "law of the gospel,"[4] and her teaching on the meaning of our existence as moral beings is ultimately based on truths that completely surpass anything discernible by human reason.

            Here I want to draw attention to these magnificent truths that God himself has made known to us preeminently through the life, death, and resurrection of his only begotten Son who, for love of us, became "flesh" (Jn 1.14). I will do so by first comparing the "law of the gospel," the "law of grace," with the natural law with respect to the persons to whom these laws are given and the purpose of these laws.[5] I will then reflect on the moral significance of our baptismal commitment as being both a call to holiness and a summons to participate, in a personal way, in the redemptive work of Christ.

Part 1. The Persons to Whom the Natural Law and the Law of Grace Are Given and the Purpose of These Laws

            A. The Natural Law

            The natural law is given, on creation, to every human being, i.e., to those bodily beings who have been made "in the image and likeness of God" (Gn 1.27), for it is a law rooted in their nature (see Dignitatis humanae, n. 14). The natural law is, in fact, the uniquely human way in which human beings "participate in" "the highest norm of human life," i.e., "the divine law — eternal, objective, and universal — whereby God orders, directs, and governs the entire universe and all the ways of the human community according to a plan conceived in his wisdom and in love" (Dignitatis humanae, n. 3), for "man has been made by God to participate in this law, with the result that, under the gentle disposition of divine providence, he can come to perceive ever increasingly the unchanging truth" (ibid.).[6]

            All creatures are subject to God's divine and eternal law insofar as they are ruled and measured by it — all, as it were, "participate in" it passively.[7] But God wills that intelligent and self-determining creatures — and this is what men are — participate more nobly in his divine and eternal law as befits their nature as beings made in his image. Thus they participate in it not only passively, by being ruled and measured by it, but also actively by coming to know ever more deeply its unchanging truth (see Dignitatis humanae, n. 3) and in this way enabling themselves to rule and measure their own free choices and actions in accord with its truth. [8] For the purpose of this law is to provide human beings with the truth needed to guide their choices and actions.[9]

            The natural law, in other words, is given to all human beings to enable them to judge truly about what they are to do and in the light of this truth to make good moral choices. Yet the natural law does not enable human beings to do the good or to avoid the evil they come to know, for they can, as experience sadly bears witness, choose to act against the truth — they can freely choose to do what they know is morally bad.

            Moreover, the human beings to whom the natural law is given are persons wounded by sin, for all are subject to original sin and to its effects — and, in addition, all who have attained the use of reason know in their own hearts that they have sinned personally — as John says, "If we say, 'We are free of the guilt of sin,' we deceive ourselves; the truth is not found in us" (1 Jn 1.8). The human beings to whom the natural law is given are persons into whose hearts concupiscence has entered.

            Concupiscence, which comes from sin and leads to sin, [10] makes it difficult for men to come to a  knowledge of the truth, i.e., of the "imperatives" of the divine and eternal law.[11] Indeed, as St. Paul testifies, he finds within himself a twofold law — the "law of his mind" (=the natural law) and the "law of his members" (=the law of concupiscence, the lex fomitis [12] [Rom 7.23]), with the result that he does not do the good he wants but rather the evil that he hates (Rom 7.15). Because of sin and concupiscence human hearts have been "hardened" (see Matt 19.8). Indeed, although the first and common principles of natural law can never be obliterated from the human heart, [13] knowledge of its more specific moral precepts is imperiled as a result of sin and concupiscence. It is precisely for this reason, the Catholic tradition holds, that God has graciously make known to us through revelation the most basic specific moral norms that we need in order to guide our everyday choices and actions, for it these norms that he gave to mankind in the law given to Moses, the law engraved on tablets of stone.[14]

            B. The New Law of Love or Grace

            The persons to whom the new law of love or grace is given are Christ's faithful, i.e., those who have been "regenerated" in the waters of baptism. These persons have, through baptism, entered into the paschal mystery of Christ: they have, in, with, and through Christ, died to sin and, again, in, with, and through Christ, have risen to a new kind of life. They have "put on Christ," become incorporated into his body, the Church, and made children of God, members of the divine family. They are the ones who can say, with John, "See what love the Father has bestowed on us in letting us be called children of God! Yet that is what we are" (1 Jn 3.1). And the purpose of the new law of love, inscribed in the hearts of God's very own children, is to enable them to live in Christ, to live worthily as children of God and members of the divine family. This brief account of the persons to whom the new law of grace is given and the purpose of this law needs to be more fully developed if we are to understand its enormous significance for our lives as moral beings and the ways in which it "perfects" or "fulfills" the natural law.

            The first way in which the new law of love fulfills the natural law is by "re-creating" the persons to whom the natural law is given. It "re-creates," "re-generates" them by uniting them to Christ. To grasp this truth rightly we must look to Jesus, the one who "fully reveals man to himself" (Gaudium et spes, n. 22).

            Jesus is true God and true man. He is true God, for "in him all the fullness of God was pleased to dwell" (Col 1.19). He is God's eternal, unbegotten "Word" (Jn 1.1). And Jesus is true man, for he is God's eternal Word made flesh, i.e., man (Jn 1.14). "Born of a woman" (Gal 4.4), he is "like his brothers in every respect" (Heb 2.17), "tempted as we are, yet without sinning" (Heb 4.15). Insofar as he is man, Jesus achieves human fulfillment by living a perfect human life, one manifesting God's goodness in a unique and special way: "I glorified you on earth, having accomplished the work you gave me to do" (Jn 17.4). And his Father crowns his work by raising him--and all persons who are one with him--from the dead. As St. Paul teaches, "Christ has in fact been raised from the dead, the first-fruits of all who have fallen asleep. Death came through one man and in the same way the resurrection of the dead has come through one man. Just as all men die in Adam, so all men will be brought to life in Christ" (1 Cor 15.20-22). Again, as man, Jesus is the "first-born of all creation" (Col 1.15), and is completed by creation united under him: God "has let us know the mystery of his purpose; the hidden plan he so kindly made in Christ from the beginning to act upon when the times had run their course to the end; that he would bring everything together under Christ as head, everything in the heavens and everything on earth" (Eph 1.9-10; see Eph 1.22-23).

            As God, Jesus unites those who are his own to the Father: "The glory which you have given me I have given to them, that they may be as one as we are one, I in them, and you in me, that they may become perfectly one" (Jn 17.22-23). Insofar as he is God, Jesus mediates to us a share in his divinity, for "from his fullness we have all received" (Jn 1.16). Indeed, in Jesus we have become "partakers of the divine nature" (2 Pet 1.4). Because his human life, death, and resurrection was the life, death, and resurrection of God's only-begotten Son, those who are united with him are in truth "begotten" anew (see Jn 3, Jesus' conversation with Nicodemus). They now become literally "children of God," members of the divine family: "See what love the Father has given us, that we should be called children of God; and so we are....Everyone who believes that Jesus is the Christ is a child of God" (1 Jn 3.1; 5.1).

            This indeed is the first great truth of our existence that Jesus, whom Thomas Aquinas rightly calls "our best and wisest friend," [15] reveals to us: God wills us into being precisely so that he can offer us his own life and make us his very own children. This is the mystery of divine filiation. We — weak human beings that we are — are the ones of whom it is written: "You are my son; this day I have begotten you" (Ps 2.7).

            Just as Jesus fully shares our humanity and our human life, so we who have been engrafted onto the "vine" which is Christ (see Jn 15.1-11) really share his divinity. In him we are literally divinized. Although our life in union with Jesus and, in, with, and through him, with the Father and the Holy Spirit will reach its completion only in the resurrection, it is absolutely essential to realize that this divine life is already, here and now, present within us. We are, now, God's children: the divine nature has been communicated to us. While always remaining human, we truly share Christ's divinity. We are literally "other Christs," truly his brothers and sisters not only in humanity but also in divinity. "Adopted" into the divine family by being "begotten" anew in baptism, we can now, with Jesus, call God our Father, our "Abba," in a new and utterly profound way. Our "hearts," on which the natural law is engraved, have been made new precisely because what is "most powerful in the law of the new covenant, and in which its whole power consists," namely, the "grace of the Holy Spirit," has been poured into them.[16]

            A second way in which the new law of love "fulfills" the natural law is by enabling those to whom it is given both to know and to do what the natural law requires. The natural law, as we have seen, is given to human persons so that they can come to know the truth about what they are to do. But the natural law, as we have seen, does not empower human persons to choose in accord with the truth they come to know. Moreover, as we have likewise seen, our struggle to come to know the truths of the natural law has been made difficult because of sin and concupiscence. The purpose of the new law of grace is to enable us to be fully God's children, to be fully the beings God wills us to be. In short, it capacitates us not only to know what we are to do if we are to be the beings God wills us to be, it also capacitates us to do everything necessary to live as God wills us to.[17] Although we are still capable of sinning even though we have been "regenerated" in the Spirit until we are confirmed in glory at the Lord's parousia, the new law given to us as Christ's faithful, "considered in itself, gives us sufficient help so that we can avoid sin." [18] By virtue of the new law of love we are made connaturally eager both to know and to do the truth. The matter is well summarized by Thomas Aquinas in the following way:

            Through baptism a person is reborn to a spiritual life, one proper to Christ's faithful, as the Apostle says (Gal 2.20), "the life I now live in the flesh I live by faith in the Son of God [who loved me and gave himself for me]." But this life belongs only to the members who are united with the head, from whom they receive sense and movement. And therefore it is necessary that through baptism a person is incorporated into Christ as his member. For just as sense and movement flow from the natural head to its [bodily] members, so from the spiritual head, who is Christ, flow to his members both a spiritual sense, which consists in the knowledge of the truth, and a spiritual movement, which operates through the inspiration of grace. Hence John says (1.14, 16), "we have seen him full of grace and truth, and of his fullness we have all received." And therefore it follows that the baptized are enlightened by Christ regarding the knowledge of the truth, and they are impregnated by him with an abundance of good works through the infusion of faith. [19]

Part 2. Our Baptismal Commitment: The Call to Holiness and to Participate in Christ's Redemptive Work

            Human persons are "re-generated," "reborn" as members of God's divine family when they are baptized, when they "die" to the old humanity wounded by Adam's sin (see Rom 5.12) and "rise" to a new kind of life, the kind made possible by union with the risen Lord: "when we were baptized we went into the tomb with him and joined him in death, so that as Christ was raised from the dead by the Father's glory, we too might live a new life" (Rom 6.4). Through baptism we have "put on Christ" (Gal 3.27) and live in union with him.

            A. The Call to Holiness

            At the heart of baptism is a free, self-determining choice whereby one renounces a life of sin and commits oneself to live henceforward worthily as a child of God, a member of Christ's body, a person called to be holy, to be "perfect, even as your heavenly Father is perfect" (Matt 5.48). The baptized person, like Jesus to whom he is united, is one whose "food is to do the will of him who sent me, and to accomplish his work" (Jn 4.34).

            Most of us were baptized as infants and, at that time, could not actually make free choices for ourselves. But others, our godparents, stood as our proxies, responding in our name to the call to die to sin and to live in a way worthy of God's own children, to be holy. And, as we grew in the household of the faith, we renewed our baptismal commitment when we received the sacrament of confirmation; and we are given the opportunity to reaffirm this commitment throughout our lives, particularly during the liturgy of the Easter vigil.

            Baptism, in short, requires the kind of choice rightly called a commitment. It is, as Germain Grisez has noted, the fundamental option of the Christian, [20] whereby the Christian freely commits himself or herself to a life in union with Jesus. In his encyclical Veritatis splendor, John Paul II emphasized that the “choice of freedom” which “Christian moral teaching, even in its biblical roots, acknowledges” as fundamental “is the decision of faith, of the obedience of  faith” (cf. Rom 16.26). This is the free choice, he continues, by citing a passage from Vatican Council II (Dei Verbum, n. 5), which in turn cites a passage from Vatican Council I (Dei Filius) “by which man makes a total and free self-commitment to God, offering the ‘full submission of intellect and will as he reveals’” (n. 66). This choice is precisely the choice to be baptized. In and through this overarching choice the Christian commits himself to become holy, to be, like his brother Jesus, a child faithful to the Father. By freely accepting in faith God's offer of grace and friendship, we commit ourselves to be holy. This is the second great truth about ourselves that Jesus makes known to us: we are called to sanctity, to holiness. As we know, the universal call to holiness is one of the central themes of Vatican Council II. This theme was luminously set forth in the Dogmatic Constitution Lumen gentium, which insists that "all in the Church, whether they belong to the hierarchy or are cared for by it, are called to holiness, according to the apostle's saying: 'For this is the will of God, your sanctification' (1 Thes 4.3; cf. Eph 1.4). This holiness of the Church is constantly shown forth in the fruits of grace which the Spirit produces in the faithful, for so it must be; it is expressed in many ways by the individuals who, each in his own state of life, tend to the perfection of love, thus edifying others" (Lumen gentium, n. 39). Continuing, this document affirms: "It is therefore quite clear that all Christians in any state or walk of life are called to the fullness of Christian life and to the perfection of love, and by this holiness a more human manner of life is also fostered in earthly society" (ibid. n. 40).

            Sanctity of life, holiness, then, is not meant only for a elete few Christians. It is rather the raison d’etre  of all Christians, for all who have been "re-generated" by the waters of baptism. Indeed, in and through our baptismal commitment we personally consecrate our lives, our whole being, to the pursuit of holiness in the choices and actions of our everyday lives, in everything that we do. As Saint Josemaria Escriva put it, "when faith is really alive in the soul, one discovers...that to follow Christ one does not have to step aside from the ordinary pattern of everyday life, and...that the great holiness which God expects of us is to be found here and now in the little things of each day." [21]

            Our baptismal commitment requires us to take up the "sword given by the Spirit" and use it as a weapon in the spiritual combat (Eph 6.17). God indeed is our Savior and Redeemer. It is through his initiative that we are now, by virtue of the love he has poured into our hearts, saved (Ti 3.5; Eph 2.5, 8; 1 Cor 15.1). He has sanctified us (1 Cor 1.2; 6.11), filling us with the fullness of Christ (Col 1.10), making us new men and women (Eph 1.15), clothing us in Christ (Gal 3.27) and making us new creatures (2 Cor 5.17), pouring his love into us through the Holy Spirit (Rom 5.5), so that we are indeed called by him and chosen (Rom 1.6; 8.28, 33; 1 Cor 1.24; Col 3.12) and made into his children, the children of light (Eph 5.8; 1 Thes 5.5; 1 Jn 3.1). But God's work in us is not completed by baptism. God continues to save us (1 Cor 1.18; 2 Cor 2.15), to make us holy and blameless (1 Thes 5.23; 3.13). And we are called and empowered by his grace to respond freely and be his co-workers in perfecting our holiness (2 Cor 7.1) by wholeheartedly dedicating ourselves to a life of righteousness and sanctification (Rom 6.19). It is our task continually to "put on the Lord Jesus Christ" (Rom 13.14), casting off the works of darkness and putting on the armor of light (Rom 13.2; Eph 5.8-11). As the children of the God who is love, our call and commitment is to "abide in him" (1 Jn 2.28; 4.13f) and walk in the light and not in darkness (1 Jn 1.7).

            B. The Call to Participate in Christ's Redemptive Work; Personal Vocation

            Jesus, our best and wisest friend, is our redeemer. The "work" he came to do was to redeem human persons and, indeed, the entire cosmos. Precisely because of our union with him--the union initially effected by our free acceptance of his saving faith in baptism — we commit ourselves to co-operate with him in his redemptive work. Jesus himself tells us that "if any man would come after me, let him deny himself and take up his cross and follow me" (Mk 8.34). St. Paul, writing to the Colossians, said that "even now I find my joy in the suffering I endure for you. In my own flesh I fill up what is lacking in the sufferings of Christ for the sake of his body, the Church" (Col 1.24). As persons united to Christ, it is our mission to complete his redemptive work in the world in which we live. An essential component of our call to holiness is the call to participate in Christ's redemptive work.

            All Christians have the common vocation to holiness and to participate in Christ's redemptive work. It is precisely for this reason that all Christians are obliged to shape their choices and actions in accord with the truth — with the moral teaching of the Church, their mother and Christ's spotless bride.

            But in addition to their common vocation, each Christian has a unique and irreplaceable vocation within the family of God. Not only are different Christians called to different ways of life in the world — the married life, the priestly life, the religious life, the life of a single person in the world — but within each state of life each Christian has his or her own unique and indispensable role to play in filling up what is lacking in Christ's afflictions and in bringing his work of redemption to completion. Vatican Council II, as Grisez so aptly notes, [22] insists that each one of us has a personal vocation to carry out as a member of Jesus' people. Indeed, as the Council Fathers said, "by our faith we are bound all the more to fulfill these responsibilities [our earthly ones as Christians] according to the vocation of each one" (Gaudium et spes, n. 43). And, as Grisez likewise notes, Pope John Paul II, who seeks to build on the teaching of St. Paul in his encyclical Redemptor hominis, emphasizes the personal vocation of each one of us as Christ’s followers. [23] In that document the Holy Father wrote: "For the whole of the community of the People of God and for each member of it what is in question is not just a specific 'social membership'; rather, for each and every one what is essential is a particular 'vocation.' Indeed, the Church as the People of God is also...'Christ's Mystical Body.' Membership in that body has for its source a particular call united with the saving action of grace. Therefore, if we wish to keep in mind this community of the People of God, which is so vast and so extremely differentiated, we must see first and foremost Christ saying in a way to each member of the community, 'Follow Me'" (Redemptor hominis, n. 71).

Personal vocation is each individual Christian's unique way of following Jesus, of walking in his path. Jesus needs the special contribution each one of us can make to complete his work of redemption. Thus, as Grisez says, "Not only do all Christians share the common vocation to particular states of life, but each Christian also has a personal vocation: his or her unique way of following Jesus." [24] And Pope John Paul II teaches us that “the fundamental objective of the formation of the lay faithful is an ever-clearer discovery of one’s vocation and the ever-greater willingness to live it so as to fulfill one’s mission.”[25]

            A third great truth, therefore, about our existence as moral beings made known to us through the revelation given in the life, death, and resurrection of Jesus, is that we are personally called to participate in Jesus' redemptive work in our own unique way.

            Thus one of the most central moral obligations of a Christian is to discern, through prayer and the grace of the Holy Spirit, his or her personal vocation to participate in Christ's redemptive work and to shape his or her life in fidelity to this vocation.


            The moral teaching of the Church, in which the truths of the natural law are indeed central, is ultimately rooted in the great supernatural truths revealed to us by Jesus. These are the truths that (1) God has made us to be the kind of beings we are precisely because he wills to give to us his very own life and make us to be his children, members of the divine family; (2) he has called us to a life of holiness in this world, in the everyday actions of our lives; and (3) he gives to each of us a personal vocation, a personal summons to participate in the redemptive work of his only-begotten Son.





1. Thus, for example, in Gaudium et spes, n. 74, the Fathers of Vatican Council II teach that there is a "natural and Gospel law" (lex naturalis et evangelica) which establishes "limits" that must be observed even by one who is defending his rights against unjust oppression. Gaudium et spes likewise proclaims that there is not just one universal principle of the natural law with unchanging binding force, but that there are many (Gaudium et spes, n. 79). On this issue see John Finnis's excellent essay, "The Natural Law, Objective Morality, and Vatican II" in Principles of Catholic Moral Life, ed. William E. May (Chicago: Franciscan Herald Press, 1981), pp. 113-150.

2. On this see Vatican Council II, Dignitatis humanae, n. 14: "The Catholic Church is by the will of Christ the teacher of truth. It is her duty to proclaim and teach with authority the truth which is Christ and, at the same time, to declare and confirm by her authority the principles of the moral order which spring from human nature itself" (emphasis added).

3. See Dignitatis humanae, n. 3: "the highest norm of human life is God's divine laweternal, objective, and universalwhereby God orders, directs, and governs the entire universe and all the ways of the human community according to a plan conceived in his wisdom and love...God has enabled man to participate in this law of his so that, under the gentle disposition of divine providence, man may be able to arrive at a deeper and deeper knowledge of unchanging truth." On this issue see my An Introduction to Moral Theology (Rev. ed., Huntington, IN: Our Sunday Visitor Publishing Division, 1994), pp. 54-59.

4. See Gaudium et spes, n. 16: "By conscience, in a wonderful way, that law is made known which is fulfilled in the love of God and one's neighbor," with footnote references to Matt 22:37-40 and Gal 5.14.

5. The material in Part 1 below summarizes and develops  some reflections originally set forth in my essay, "Christian Faith and Its 'Fulfillment' of the Natural Moral Law," Anthropotes 7 (1991) 155-169.

6. The conciliar text does not explicitly use the expression "natural law" to designate man's participation in God's eternal divine law. However, that this was the mind of the Council is made clear by the fact that an official footnote is appended to this paragraph, explicitly drawing attention to some key texts of St. Thomas, namely Summa theologiae, q. 91, a. 1; q. 93, aa. 1 and 2. In q. 93, a. 2 Thomas says: "Every rational creature knows it [the eternal law] according to some irradiation if it, greater or less. For all knowledge of the truth is a certain irradiation and participation in the eternal law, which is unchangeable truth...but all men somehow know its truth, at least with respect to the common principles of the natural law."

7. See Summa theologiae, 1-2, q. 91, a. 2, ad 3.

8. Ibid., q. 91, a. 2 and q. 93, a. 6. On this point it is worth consulting D. O'Donoghue, "The Thomist Concept of Natural Law," Irish Theological Quarterly 22 (1955) 89-109, especially 93-94.

9. See Summa theologiae, 1-2, q. 91, a. 2.

10. See St. Augustine, De Nuptiis et Concupiscentia I, 25 (PL 44, 429-430). The Council of Trent made St. Augustine's teaching on concupiscence its own; see Henricus Denzinger and Adolphus Schoenmetzer (eds.), Enchiridion Symbolorum (34th ed. Romae: Herder, 1973), n. 1515.

11. Thus in Dignitatis humanae, n. 3, the Council Fathers speak of man perceiving and acknowledging the "imperatives of the divine law," while in Gaudium et spes, n. 16, they note the baleful effects sin can have on human conscience.

12. On this see Summa theologiae, 1-2, q. 91, a. 6.

13. See Summa theologiae, 1-2, q. 94, a. 6.

14. See ibid.,] q. 91, a. 4; q. 94, a. 2.

15. Summa theologiae, 1-2, 108, 4, sed contra: "Christus maxime est sapiens et amicus."

16. Ibid., q. 106, a. 1.

17. See ibid., q. 106, a. 1, ad 2.

18. Ibid.

19. Ibid., 3, q. 69, a. 5.

20. Germain Grisez, The Way of the Lord Jesus, Vol. 1, Christian Moral Principles (Chicago: Franciscan Herald Press, 1983), p. 551.

21. Saint Josemaria Escriva, Friends of God (New Rochelle, NY: Scepter Press, 1986), p. 271, n. 312.

22. Grisez, Christian Moral Principles, p. 559.

23. Ibid., p.560.

24. Ibid., p. 560.

25. Pope John Paul II, Apostolic Exhortation on the Vocation and the Mission of the Lay Faithful in the Church and in the World (Christifideles laici), n. 58.

Copyright ©; William E. May 2003

Version: 28th April 2003

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