The following is a research paper written as part of my graduate studies in Theology at Franciscan University of Steubenville
“All nations seem, more or less, to have forgotten the true notion and origin of marriage,” Pope Leo XIII said in his encyclical in 1880, and it seems even truer today.
Many have come to believe that marriage is “invented by man” and that “sexual intercourse is … solely a natural response to human instinct and human need.” However, as the Catholic Conference of Catholic Bishops states:“It is not just instinct, human desire, or need which must be considered in human sexual activity. One must understand human life and the human spirit, which transcends biology and humanistic philosophy. Human sexual activity cannot be separated from the nature and dignity of human life and the process by which that life is transmitted.” This transcendence is the human soul, and this dignity of human life is the image of God.
As Christians should understand it, sex was created by God as a sacred and exclusive gift for marriage, which is “the wise institution of the Creator to realize in mankind His design of love.” In response to the secular culture, the Church has expressed how marriage (including the marital act) is not only very good, but a sacred symbol of God’s love—which is a free, total, faithful, and fruitful gift of self.
Marriage and Sexuality are Very Good
When God created the earth, the stars, and the plants and animals, He said that each was “good,”—but after He created human beings, He said they were “very good.” This shows the great dignity humanity has above the rest of creation, and this applies to the whole human person—not only to the human soul, but to the body and human sexuality as well.
Because “man is a person in the unity of his body and his spirit,” therefore “the body can never be reduced to mere matter: it is a spiritualized body, just as man’s spirit is so closely united to the body that he can be described as an embodied spirit.” Because of this unity of body and soul, “man is not allowed to despise his bodily life, rather he is obliged to regard his body as good and honorable since God has created it and will raise it up on the last day.” And because the person is a union of body and soul, “It is also through the body that man and woman … form a ‘communion of persons’ in marriage”—it is a union of their whole persons, not merely their bodies.
In this way, “The sexual characteristics of man and the human faculty of reproduction wonderfully exceed the dispositions of lower forms of life,” who do not possess immortal souls nor are created in the image of God as humans are. Because of this dignity of human persons, “the acts themselves which are proper to conjugal love and which are exercised in accord with genuine human dignity must be honored with great reverence.”
Fallen, But Redeemed
The fall of man, however, damaged his relationship with God, himself, and others; but through the coming of the Savior, humanity’s relationships can experience a restoration of their original goodness. For Christ, who is “the image of the invisible God” and “the perfect man,” thus “restores the divine likeness which had been disfigured from the first sin onward.” Through the Holy Spirit whom Christ sent to dwell within man, “the whole man is renewed from within, even to the achievement of ‘the redemption of the body.’” In this way, “The bodies of the husband and wife” are redeemed and made holy by becoming “the dwelling-place of the Holy Spirit.”
Marriage in the Image of the Trinity
Furthermore, human sexuality and marriage are not only very good, but are created in the image of God. Marriage is an image of God’s love, first of all, as a symbol of the Trinity. From the very beginning, “God created mankind in his image.” As Pope Paul VI expressed in Humanae Vitae, “Married love particularly reveals its true nature and nobility when we realize that it takes its origin from God, who ‘is love.’” This image of love is first of all the community of persons in the Trinity: “Let us make man in our image,” God said, “after our likeness.” Pope John Paul II explains how God created humanity from the “pattern and inspiration” of “the mystery of his Being, which is already here disclosed as the divine ‘We.’” He describes how “the ‘communion’ of persons is drawn in a certain sense from the mystery of the Trinitarian ‘We,’ and therefore ‘conjugal communion’ also refers to this mystery.”
Because God is love through being a communion of persons, He created humanity also for love and communion, not only with Himself but with each other, expressed especially through the complementarity and communion between male and female: “God created man in his own image, in the image of God he created him; male and female he created them.” John Paul II notes how “Man is created ‘from the very beginning’ as male and female…. Hence one can discover, at the very origins of human society, the qualities of communion and of complementarity.” We see that from the beginning “God did not create man as a solitary,” and that “Their companionship produces the primary form of interpersonal communion.” It is evident from Genesis that “It is not good for the man to be alone,” and therefore God made “a helper suited to him.” Finally, “It is striking that the ‘image of God’ here refers to the couple, ‘male and female’…. inasmuch as he is also the Creator, the fruitfulness of the human couple is a living and effective ‘image,’ a visible sign of his creative act,” and “becomes a symbol of God’s inner life…. for in the Christian vision of the Trinity, God is contemplated as Father, Son and Spirit of love.”
In other words, just as the love between the Father and the Son manifests itself as the person of the Holy Spirit—in a similar way, the love between the Spouses is so powerful and fruitful that it creates a third person, the new child produced from the two. In this way especially, “The triune God is a communion of love, and the family is its living reflection.”
Marriage in the Image of Christ and the Church
Secondly, marriage is in the image of God because it is a symbol of the love between Christ the Bridegroom and His bride, the Church. John Paul II explains how “Jesus describes himself in the gospels as ‘the Bridegroom,’” a description of God “which had already been used in the Old Testament” and which “reveals the essence of God and confirms his immense love for mankind. But the choice of this image also throws light indirectly on the profound truth of spousal love.”
In particular, Ephesians tells husbands to love their wives “even as Christ loved the church and handed himself over for her.” Here, it tells us that wives are to act in obedience to their husbands as the Church is in obedience to Christ; and husbands are to act in imitation of Christ, loving their wives with sacrificial love. In this way, the spouses are to love and respect one another through their marriage and through the marital act itself, acting as imitations of how Christ loved the Church and sacrificed Himself for her: “Thus, following Christ … by the sacrifices and joys of their vocation and through their faithful love, married people can become witnesses of the mystery of love which the Lord revealed to the world by His dying and His rising up to life again.”
This incredible, boundless love of Christ is the only perfect example of love, without which humanity cannot come to understand the true meaning of love. As John Paul II expressed: “Could we even imagine human love without the Bridegroom and the love with which he first loved to the end? Only if husbands and wives share in that love and in that ‘great mystery’ can they love ‘to the end.’ Unless they share in it, they do not know ‘to the end’ what love truly is and how radical are its demands.”
Marriage and the Eucharist: A Foretaste of the Wedding Feast of the Lamb
This union between Christ and the Church is especially expressed and brought about by the communion of the Eucharist—which the unity of the spouses also reflects and is spiritually strengthened by.
John Paul II describes the Eucharist as “The liturgical crowning of the marriage rite,” which is “the sacrifice of that ‘Body which has been given up’ and that ‘Blood which has been shed,’” and “which in a certain way finds expression in the consent of the spouses.” Just as the Church becomes one Body in Christ, so in a similar way the spouses become “one flesh” in the marital union: “Spouses are called to celebrate their conjugal love by becoming one flesh in the Lord.” Pope Francis affirms this “close bond between married life and the Eucharist,” since “the food of the Eucharist offers the spouses the strength and incentive needed to live the marriage covenant each day as a ‘domestic church.’” Thus, while being a part of Christ’s Church whom He gave Himself up for, marriage seeks to imitate this love Christ has for His Church.
Furthermore, as Pope Francis says, “The family’s communal journey of prayer culminates by sharing together in the Eucharist. There, spouses can always seal anew the paschal covenant which united them and which ought to reflect the covenant which God sealed with mankind in the cross.”
Finally, the Eucharist and Holy Matrimony reflect each other as sacraments, since they are both meant to bring about the unions which they signify—a union between Spouses, and a union between Christ and His Church. Both the communion of Marriage and especially this Eucharistic Communion is a foretaste of the union one will have with God in Heaven, a foretaste of “the wedding feast of the Lamb.”
Marriage as a Sacrament
Furthermore, at the Wedding at Cana, Marriage was established by Christ as a Sacrament, a covenantal union between the Spouses and God. When Jesus turned water into wine, this prefigured the wine which would be turned into His own blood. Thus, “What marriage is in nature becomes, by the will of Christ, a true sacrament of the New Covenant, sealed by the blood of Christ the Redeemer.” As the Second Vatican Council proclaims, just “as God of old made Himself present to His people through a covenant of love and fidelity, so now the Savior of men and the Spouse of the Church comes into the lives of married Christians through the sacrament of matrimony.”  And, as the Bridegroom of the Church, “He abides with them thereafter so that just as He loved the Church and handed Himself over on her behalf, the spouses may love each other with perpetual fidelity through mutual self-bestowal.”
As a Sacrament, marriage is “a sign and source of that peculiar internal grace by which ‘it perfects natural love, it confirms an indissoluble union, and sanctifies both man and wife.’” By this Sacrament, “they are strengthened and, one might almost say, consecrated to the faithful fulfillment of their duties.” Not only this, but through the sacrament of marriage, “Authentic married love is caught up into divine love,” of which it is a symbol, “that this love may lead the spouses to God.”
Thus the ultimate goal of marriage is to lead each other Heaven—to union with God. That is why Pope Francis emphasizes that “A positive experience of family communion is a true path to daily sanctification and mystical growth, a means for deeper union with God…. a path which the Lord is using to lead them to the heights of mystical union.” In this way, again, the sacrament of Holy Matrimony is truly meant to bring about the grace which it signifies—union between the spouses and ultimately with God.
It is important to note, however, that “in order that the grace of this sacrament may produce its full fruit, there is need … of the cooperation of the married parties; which consists in their striving to fulfill their duties to the best of their ability and with unwearied effort.” Pope Francis expressed well that “no family drops down from heaven perfectly formed; families need constantly to grow and mature in the ability to love. This is a never-ending vocation born of the full communion of the Trinity, the profound unity between Christ and his Church.” Thus, it is only “Gradually, ‘with the grace of the Holy Spirit,’” that the spouses “grow in holiness through married life, also by sharing in the mystery of Christ’s cross, which transforms difficulties and sufferings into an offering of love.’ Moreover, moments of joy, relaxation, celebration, and even sexuality can be experienced as a sharing in the full life of the resurrection.”
Marriage in the Image of God’s Love: Free, Total, Faithful, Fruitful
What is this true love meant to be like, then—this love of God which the spouses seek to emulate? Humanae Vitae outlines the fundamental aspects of true marital love as necessarily free, total, faithful, and fruitful.
Love must, first of all, be free in order to be real love. God’s love is evidently free: He freely loves within Himself as the Trinitarian communion, and He chose to create the world and humanity out of love—not out of any need or selfish desire, since He is totally self-sufficient and perfect in Himself. Furthermore, Christ’s sacrifice for His Church was a freely chosen sacrifice, as He chose to give Himself up for us, saying to the Father “not my will but yours be done.”
Furthermore, it is necessary that love be given freely in order to truly be love, because love is inherently a free gift of oneself; and it is for this reason that God gave human beings free will, “so that he can seek his Creator spontaneously, and come freely to utter and blissful perfection through loyalty to Him.” This free will of man, given so that man may freely choose the good and love God, “is an exceptional sign of the divine image within man,” and therefore “man’s dignity demands that he act according to a knowing and free choice … not under blind internal impulse nor by mere external pressure.… emancipating himself from all captivity to passion.”
Thus, “although matrimony is of its very nature of divine institution, the human will, too, enters into it and performs a most noble part. For each individual marriage … arises only from the free consent of each of the spouses.” This is also one of the reasons why man is different from other animals—because He has the capacity to freely choose and to love: “This love is above all fully human, a compound of sense and spirit. It is not, then, merely a question of natural instinct or emotional drive. It is also, and above all, an act of the free will.” This is why the marital union is “entirely different both from the union of animals entered into by the blind instinct of nature alone in which neither reason nor free will plays a part, and also from the haphazard unions of men, which are far removed from all true and honorable unions of will and enjoy none of the rights of family life.”
Finally, this is why “It is the spouses who … are the ministers of the Sacrament of Matrimony”—and if consent is not freely given (such as if it is given under external pressures or is severely hindered by the emotional or psychological state of the individual), then the marriage is not truly valid.
Furthermore, the love of God which the spouses wish to emulate is total. This total giving of oneself is expressed above all in Christ’s total sacrifice on the cross: for “he humbled himself, becoming obedient to death, even death on a cross,” and “No one has greater love than this, to lay down one’s life for one’s friends.”
As expressed in Humanae Vitae, the love between spouses seeks to emulate this total self-gift of Christ, for “Whoever really loves his partner loves not only for what he receives, but loves that partner for the partner’s own sake, content to be able to enrich the other with the gift of himself.” A love which is total is that which loves because it recognizes the dignity of the other made in the image of God. Marriage and the marital act are meant to “promote that mutual self-giving by which spouses enrich each other with a joyful and a ready will,” and “the unity of marriage will radiate from the equal personal dignity of wife and husband, a dignity acknowledged by mutual and total love.”
As expressed by the Second Vatican Council: man “cannot fully find himself except through a sincere gift of himself.” John Paul II explains how “this might appear to be a contradiction, but in fact it is not. Instead it is the magnificent paradox of human existence: an existence called to serve the truth in love. Love causes man to find fulfillment through the sincere gift of self.” Mankind was made out love and for love, and this means to be a self-gift.
Faithful and Permanent
Furthermore, a love that is total requires that it also be faithful and permanent. “By its very nature the gift of the person must be lasting and irrevocable,” says John Paul II, and “the indissolubility of marriage flows in the first place from the very essence of that gift: the gift of one person to another person.” Pope Francis also describes marriage as “the experience of belonging completely to another person,” and he quotes John Paul II in saying that this permanent fidelity is an “interior requirement of the covenant of conjugal love,” since “a person who cannot choose to love for ever can hardly love for even a single day.”
Finally, as mentioned previously, this love is meant to imitate God’s love, which is always faithful and everlasting. In particular, Christ’s self-gift on the cross was a total and final offering—one which afterwards granted the Holy Spirit to dwell within His Church and the Eucharist to sustain her, so that in these ways He would truly be with her “until the end of the age,” until (by the grace of this same sacrifice) His Church could enter Heaven and live eternally in union with her Bridegroom.
Because this love and union between Christ and His Church is an eternal one, marriage too was made to be an eternal union until its fulfillment in Heaven: “the marriage of Christians recalls that most perfect union which exists between Christ and the Church … which union, as long as Christ shall live and the Church through Him, can never be dissolved by any separation.” Therefore, as Pope Pius XI says:
Matrimonial faith demands that husband and wife be joined in an especially holy and pure love, not as adulterers love each other, but as Christ loved the Church … which of a truth He embraced with a boundless love not for the sake of His own advantage, but seeking only the good of His Spouse. The love, then, of which We are speaking is not that based on the passing lust of the moment nor does it consist in pleasing words only, but in the deep attachment of the heart which is expressed in action, since love is proved by deeds.
Furthermore, since God is the creator, establisher, and model of marriage, He (speaking through Scripture as well as the Church) is also the final authority on marital matters. In the Scriptures, Christ Himself confirmed the necessity of marital faithfulness and the irrevocable character of marriage. When the Pharisees argue with Him over the Mosaic Law which allowed for divorce, Jesus emphasizes the passage from Genesis which says that “a man leaves his father and his mother and cleaves to his wife, and they become one flesh.” Jesus explains quite clearly: “So they are no longer two but one flesh. What therefore God has joined together, let not man put asunder…. For your hardness of heart Moses allowed you to divorce your wives, but from the beginning it was not so.” Furthermore, Christ firmly said that “Everyone who divorces his wife and marries another commits adultery, and the one who marries a woman divorced from her husband commits adultery.”
Finally, it is important to mention how marital fidelity is not only possible, but it is beneficial—while divorce is harmful both to the spouses and to the children involved. Humanae Vitae points out that, “though this fidelity of husband and wife sometimes presents difficulties … [t]he example of countless married couples proves not only that fidelity is in accord with the nature of marriage, but also that it is the source of profound and enduring happiness.”
Pope Pius XI also discusses the merits of marital fidelity, by which “both husband and wife possess a positive guarantee of the endurance of this stability which that generous yielding of their persons and the intimate fellowship of their hearts by their nature strongly require, since true love never falls away.” Furthermore, he says, “a strong bulwark is set up in defense of a loyal chastity against incitements to infidelity, should any be encountered either from within or from without; any anxious fear lest in adversity or old age the other spouse would prove unfaithful is precluded and in its place there reigns a calm sense of security.” Additionally, the Second Vatican Council maintains that it is not only the “intimate union” of the spouses, but also “the good of the children” which requires a “total fidelity on the spouses and argue for an unbreakable oneness between them.” Pope Leo XIII points out the great evils “that flow from divorce,” namely that:
Matrimonial contracts are by it made variable; mutual kindness is weakened; deplorable inducements to unfaithfulness are supplied; harm is done to the education and training of children; occasion is afforded for the breaking up of homes; the seeds of dissension are sown among families; the dignity of womanhood is lessened and brought low, and women run the risk of being deserted after having ministered to the pleasures of men.
Nonetheless, the Church has allowed separation of spouses in extreme cases (though not a true divorce or remarriage):
When, indeed, matters have come to such a pitch that it seems impossible for them to live together any longer, then the Church allows them to live apart…. yet she never ceases to endeavor to bring about a reconciliation, and never despairs of doing so. But these are extreme cases; and they would seldom exist if men and women entered into the married state with proper dispositions, not influenced by passion, but entertaining right ideas of the duties of marriage and of its noble purpose.
The Church also at times may grant an annulment of a marriage in a case where the marriage was not truly valid in the first place (such as if one of the substantial aspects of marriage as free, total, faithful, or fruitful was absent or severely hindered from the beginning), in which case a first true marriage afterwards would be allowed.
Finally, marital love in the image of God is fruitful. This is because, first of all, a total love requires fruitfulness—truly giving oneself fully to the other includes giving oneself in every aspect. Fully giving to and accepting the other includes accepting the fruitfulness, the child, which comes from such a union of love. “When a man and woman in marriage mutually give and receive each other in the unity of ‘one flesh,’” says John Paul II, “the logic of the sincere gift of self becomes a part of their life. Without this, marriage would be empty; whereas a communion of persons, built on this logic, becomes a communion of parents. When they transmit life to the child, a new human ‘thou’ becomes a part of the horizon of the ‘we’ of the spouses, a person whom they will call by a new name.” Furthermore, the United States Conference of Catholic Bishops describes “the profound meaning of a life of intimacy,” of the marital union, as “that communion of two persons who must be open to each other in a mutual self-donation that reaches its apex in the loving union that bears fruit in children.” A total gift of oneself includes the gift of one’s fruitfulness, which is a profound gift from God.
This fruitfulness is also a symbol of the love within the Trinity and between Christ and the Church. John Paul II explains that, when God said, “Be fertile and multiply,” there is “present here the analogy of begetting and of fatherhood and motherhood.” Just as the spouses’ love for each other begets a new person, so too, in a similar way, the love between the Father and the Son is so powerful that it is manifested as a third person, the Holy Spirit. Furthermore, Christ’s love for the Church is also fruitful, since it merited for us salvation, reconciling us to the Father and granting us “the first-fruits of the Spirit.” Through the coming of the Son, the Spirit of love comes to dwell within His Church.
Furthermore, John Paul II points out here how “no living being on earth except man was created ‘in the image and likeness of God.’” Because this love between the spouses is in the image of the Trinitarian God and of Christ the Bridegroom, the marital act is far from merely a means of pleasure, nor is it merely a means of union (though this is a vital aspect)—it is inherently a life-giving act, an act which leads to the creation of a family, and in being fruitful it is a greater and more beautiful union of love. “Their unity,” says John Paul II, “rather than closing them up in themselves, opens them towards a new life, towards a new person.”
The Church’s documents affirm that the unitive and procreative aspects of the marital act are inseparable. The Second Vatican Council asserts that “Marriage and conjugal love are by their nature ordained toward the begetting and educating of children,” and describes children as “the supreme gift of marriage.” Humanae Vitae affirms this and explains why this is so:
This particular doctrine … is based on the inseparable connection, established by God, which man on his own initiative may not break, between the unitive significance and the procreative significance which are both inherent to the marriage act. The reason is that the fundamental nature of the marriage act, while uniting husband and wife in the closest intimacy, also renders them capable of generating new life—and this as a result of laws written into the actual nature of man and of woman.
Affirming Humanae Vitae, the United States Conference of Catholic Bishops explains that the unity and fecundity of marriage “are inseparable—not in the sense that both must be achieved in every act of conjugal intimacy, but in the sense that one may not deliberately act against either good in any act of conjugal intimacy.” This affirms what Humanae Vitae said, that “an act of mutual love which impairs the capacity to transmit life… frustrates [God’s] design … and contradicts the will of the Author of life.” It contradicts the way that man was created and devalues the marvelous gift of the new life of a human person. “Human life is sacred,” as Pope John XXIII has said; “From its very inception it reveals the creating hand of God.”
Thus, one can see how the Church has responded to the modern ideas of sexuality and marriage with the truth that Holy Matrimony is made in the image of God—in the image of the Trinity and of Christ and the Church—in the image of a love that is a free, total, faithful, and fruitful gift of oneself. “In the face of a society that has lost sight of the profound meaning of marital intimacy,” we as Catholics need to not merely condemn the modern culture, but impress on our culture a positive sense of this sacredness. We, as Catholics in “a society that has separated sexuality from married love and intimacy from procreation” must therefore “call everyone to listen once again to the wisdom of Humanae Vitae and to make the Church’s teaching the foundation for a renewed understanding of marriage and family life.”
Read more of my articles on Marriage, Sexuality, and Theology of the Body here.
God bless and keep you!
 Pope Leo XIII, Arcanum (On Christian Marriage) (1880), <http://www.vatican.va/content/leo-xiii/en/encyclicals/documents/hf_l-xiii_enc_10021880_arcanum.html>. 7.
 Pope Pius XI, Casti Connubii (On Christian Marriage) (1930), <https://www.papalencyclicals.net/pius11/p11casti.htm>.
 Pope Francis, Amoris Laetitia (2016), <http://www.vatican.va/content/francesco/en/apost_exhortations/documents/papa-francesco_esortazione-ap_20160319_amoris-laetitia.html>.1.
 Pope Paul VI, Humanae Vitae (On the Regulation of Birth) (1968) <http://www.vatican.va/content/paul-vi/en/encyclicals/documents/hf_p-vi_enc_25071968_humanae-vitae.html>. 8.
 Genesis 1:31.
 Pope John Paul II, Gratissimam Sane (Letter to Families) (1994), <http://www.vatican.va/content/john-paul-ii/en/letters/1994/documents/hf_jp-ii_let_02021994_families.html>. 19.
 Pope Paul VI, Second Vatican Council, Gaudium et Spes (Pastoral Constitution on the Church in the Modern World) (1965), <http://www.vatican.va/archive/hist_councils/ii_vatican_council/documents/vat-ii_const_19651207_gaudium-et-spes_en.html>. 15.
 Gratissimam Sane 8.
 Gaudium et Spes 51.
 Colossians 1:15.
 Gaudium et Spes 22.
 Gaudium et Spes 22; Romans 8:23.
 Gratissimam Sane 18; Cor 6:19.
 Genesis 1:27.
 Humanae Vitae 8; 1 John 4:8.
 Genesis 1:26, emphasis added.
 Gratissimam Sane 6.
 Ibid. 8.
 Genesis 1:27.
 Gratissimam Sane 6.
 Gaudium et Spes 12.
 Genesis 2:18.
 Amoris Laetitia 10-11.
 Ibid. 10-11.
 Matthew 9:15.
 Gratissimam Sane 18.
 Ephesians 5:25.
 Ephesians 5:21-24.
 Gaudium et Spes 52.
 Gratissimam Sane 19.
 Ibid. 11.
 Genesis 2:24; Matthew 19:5; Mark 10:8; Ephesians 5:31.
 Human Sexuality from God’s Perspective 2.
 Amoris Laetitia 318.
 Revelation 19:9.
 Gratissimam Sane 18.
 Gaudium et Spes 48.
 Casti Connubii 38.
 Humanae Vitae 25.
 Gaudium et Spes 48.
 Amoris Laetitia 316.
 Casti Connubii 111.
 Amoris Laetitia 325.
 Relatio Finalis (2015) 87, as quoted by Amoris Laetitia 325.
 Ibid. 317.
 Luke 22:42.
 Gaudium et Spes 17.
 Casti Connubii 6.
 Humanae Vitae 9.
 Ibid. 7.
 Gratissimam Sane 10.
 Philippians 2:8.
 John 15:13.
 Humanae Vitae 9.
 Gaudium et Spes 49.
 Ibid. 24.
 Gratissimam Sane 11.
 Gratissimam Sane 11.
 Amoris Laetitia 319; Pope St. John Paul II, Homily at Mass with Families, Cordoba, Argentina (8 April 1987), 1161-1162, as quoted from Amoris Laetitia 319.
 Jeremiah 31:3; Deuteronomy 7:92; Timothy 2:13; Psalm 91:4; Romans 8:38-39
 Matthew 28:20.
 Casti Connubii 36.
 Ibid. 23.
 Genesis 2:24, emphasis added.
 Matthew 19:6, 8.
 Luke 16:18.
 Humanae Vitae 9.
 Casti Cannubii 37.
 Ibid. 37.
 Gaudium et Spes 48.
 Arcanum 29.
 Ibid. 41.
 Gratissimam Sane 11.
 Human Sexuality from God’s Perspective 2.
 Genesis 1:28.
 Gratissimam Sane 6.
 Romans 8:23.
 Gratissimam Sane 6.
 Ibid. 8.
 Gaudium et Spes 50.
 Humanae Vitae 12.
 Human Sexuality from God’s Perspective 3.
 Humanae Vitae 13.
 Mater et Magistra 194, as quoted by Humanae Vitae 13.
 Human Sexuality from God’s Perspective 5.