We Christians realize that everything that exists has its origin in the Father, the Son and the Holy Spirit. We became a Christian through baptism in the name of the three divine Persons. And everything in our lives is marked by the sign of the Cross, in the name of the Father and of the Son and of the Holy Spirit, according to the words of Jesus himself (Mt 28:19). But what does faith in the Trinity mean for our own life? How does it affect our daily existence, our family, our work, our rest?
Although we will only understand in heaven to what extent the Trinity is our true home, to what extent our life is hidden with Christ in God (Col 3:3), our Christian faith already directs our steps towards this Mystery that contains the answer to all our questions and tells us who we really are. The Mystery of the Trinity profoundly changes our view of the world and transfigures our existence. It illumines what, taken by itself, could be seen as banal or insignificant, with a powerful light. Among the many aspects that faith in the Trinity entails, we will consider here two that are closely intertwined: the depth of this Mystery and the divine value of human love.
The Mystery of mysteries
Theologians, saints and those who have experienced God intensely have shown, right from the first generations of Christians, a special predilection for the Mystery of the Trinity (Mysterium Trinitatis). In daily life we also often speak about a mystery, although in the sense of something that it is hard to fathom, like knowing who the criminal is in a detective novel, or what the solution is to an equation or a difficult problem. In all these cases the term refers to the limits of our ability to know. But when we speak about the Mystery of God, the question no longer concerns us alone, but above all God himself and his infinite depths. The Mystery of God is not unfathomable because it is dark but, on the contrary, because it is too luminous; the eyes of our intellect are dazzled by looking at it, as happens when we look at the sun in broad daylight.
A pious medieval legend, represented also in magnificent paintings, recounts that one day Saint Augustine was walking along the beach trying to understand how God could be both one and three. He came across a child who was using a seashell to pour water from the sea into a hole dug in the sand. When asked what he was doing, the child said he was trying to put the whole sea in the hole. The great Father of the Church tried to make him see how impossible this was; but the boy replied that it was even more absurd to try to understand the Mystery of the Trinity. The Mystery of God is like the immensity of the sea, like the blinding light of the sun. Entering into this Mystery means “plunging into the ocean of infinite love,” “diving into that immense sea.”
During one of his catechetical trips, Saint Josemaría pointed to the right way to speak about God:“When people tell you that they don’t understand the Trinity and Unity, you should reply: I don’t understand it either, but I love it and venerate it. If I understood God’s greatness, if God fit into this poor head of mine, my God would be very small. And yet, He does fit -- He wants to fit -- in my heart, in the immense depth of my soul, which is immortal.” A totally understandable God would not be a mystery but something very small. The Christian paradox is that, although the infinite Trinity cannot be understood by our intellect, He dwells in us, in our heart.
The difficulty in understanding the Mystery of the Father, Son and Holy Spirit is not due to its being an absurdity, but to its being a Mystery of Love: a communion of Persons. Our God is Mystery because He is Love: everything in Him is perfect and eternal Gift. And the created world is an expression of that Love. Through the world and the people around us, we can understand why faith is needed to grasp this truth, which not even the greatest philosophers could discover without Revelation. It is not a matter of believing in what is absurd, but of entering into the personal dimension of the Mystery, which we can only achieve when we open our hearts. “Lord, thank you because you are so great that you don’t fit in my head, and thank you also because you fit in my heart!”
Why does God hide himself in his Mystery? In reality it is not that He hides himself. Even among human beings it is true that the intimacy of another person’s soul can only be known through a voluntary act of revealing what is in one’s heart, one’s memories, dreams, worries and fears. Although some of this can be guessed from the outside, for another person to grasp what is deep inside us, a “revelation” of ourselves is needed; and the one who shares in this “revelation” needs to truly understand and assimilate it. We should not be surprised that the Mystery of God surpasses us. Our eyes need to become accustomed little by little to its light. Therefore, if in daily life we need to learn “to remove our sandals before the sacred ground of the other,” before the Mystery of the Trinity the first attitude we need is humility and a deep respect, because we are entering into the space of Freedom and Gift, the Freedom and Gift that are at the origin of Love, of all love.
The Love of loves
“The only true love is God’s Love,” Saint Josemaría wrote in 1931. Immersing ourselves in the depth of the Mystery of the triune God leads us to read the world and history in its light, which is the true light (Jn 1:9). Just as if we went from trying to decipher a text in the shade to reading it in full sunlight, and we discovered that we were really not understanding anything. God is love (1 Jn 4:16) because He is an eternal communion of three Persons, who give themselves reciprocally without reserve: three Persons united in an absolute and eternal way by a relationship of total and free Self-giving. The meaning of the world and of the existence of each human being rests on that authentic freedom, on that “trinitarian current of Love.”
The Father really generates the Son, giving him everything that he himself is, and not simply something that he possesses. The first divine Person is Father with all his being, Father without limits, in such a way that the Son generated by him not only resembles him, but is one single thing with him: he is God himself in his eternity and infinity. The Son, the perfect Image of the Father, gives himself anew to him, that is, he responds to the gift that he receives, giving himself totally to the Father, just as the Father has given himself to the Son. And the Gift that the Father and the Son eternally exchange is the Holy Spirit, third Person of the Trinity. The Holy Spirit is the Love that unites the first two Persons, and he is God, because he is one with them. Thus our God is one and triune precisely because he is absolute Love, because he is perfect Gift, without reservations, without conditions: the Love we all dream of.
Saint Augustine, although he came to realize the limitation of our human concepts, explained it in a way that helps us to glimpse the intimate life of the Trinity. Love, he wrote in his treatise on the Trinity, always implies the presence of the lover, the one who is loved and their love. Similarly, to be able to speak of a gift, there must be someone who gives, another who receives and also that which is given: the gift, the present. Only with this triad is there Love. And when the Love or the Gift is infinite, and therefore enters into the space of the Mystery of God, these three terms are infinite and perfect. So that our God is one and triune precisely because he is Love. From this boundless Love there arises, and towards it is directed, “the desire that we all have for infinity, the nostalgia that we all have for the eternal.”
One of the adjectives used by Christians to describe the Trinity is Blessed. God is the fullness of blessedness, of happiness, and He wants to share it, which is why He has created all things: to share with us his infinite joy. The world around us, and the existence of each person, has its origin in the eternal reciprocal Gift that is the Life of the Father, Son and Holy Spirit. We exist because we are loved by the three divine Persons. That is why the human being’s value is infinite. Seen in this light, “both the origin and goal of creation, which is love, seem marvellous to us. It is an absolutely disinterested love, because God has no need of us. Rather we are the ones who need Him.”
Since the world arises from the overflow of the Love of the three divine Persons, the meaning of life for those who believe in the Trinity is love. And that is why all true love refers, in its deepest core, to the Trinity, as Pope Francis recently stressed, recalling the teachings of Saint John Paul II. Therefore the fundamental importance of the family for the Christian faith is not only linked to the moral dimension or to sociological considerations. The fruitful relationship of the spouses is the guiding image in the encounter with the Mystery of the Trinity: “God the Trinity is a communion of love, and the family is its living reflection.”
Christians, then, know that the first principle of any reality is not an abstract unity or a universal idea, but a communion of Persons: a radiant communion of happiness. The ground of all reality, the deepest truth, is found in interpersonal relationships. The meaning of happiness is a mystery that begins to be revealed precisely in those relationships; the meaning of life is found in those depths. Friendship, service to others, fraternity, love in all its forms, are not just beautiful words or positive practices suggested by a good heart. Careful cultivation of interpersonal relationships is the most realistic and effective way to act, since the foundation of all reality is Trinitarian. Sin, by contrast, is essentially superficial, and fails to see what really counts in life. Sin closes us off from others and involves a true existential myopia, which we all need to have corrected. The revelation of the Trinity and the faith that unfolds from this Mystery is a balm for our eyes; it shows us how to truly win out in life, and how to win over others for eternal Life.
The gaze of the saints, who know they are sinners like everyone else, moves between Heaven and earth. The saints recognize that true self-fulfilment is found in love and service. Gestures of affection such as a hug, or of courtesy such as a handshake, echo the love of the Trinity, because they signify the desire or availability to be one in the other, as the divine persons are. He who has seen me has seen the Father, Jesus says to Philip (Jn 14:9). He who sees the Son sees the Father, because the Father is in the Son and the Son in the Father: they are the fullness of Love. This is the life of the Trinity, the life to which God calls us. The life of the Father is to give his life to the Son; the life of the Son is to give thanks to the Father with his life; the Holy Spirit is that Life for the Other.
Contemplating the world in the light of the Trinity leads to a new perspective: if the principle of all things is our God, then at the origin and destiny of reality is found the Love of the Father for the Son and of the Son for the Father. Scripture gives us a glimpse of this in the hovering of the Spirit of God over the waters (cf. Gen 1:2). The Love of the Trinity embraces the entire universe. And, in a more explicit way, taking up the story of creation in the light of the incarnation of the Word, the prologue to the Fourth Gospel says that all things were made through him (Jn 1:3). The Filiation of Christ is reflected in all things, and everything is directed to Him (cf. Eph 1:10). The distant stars, the deep sea, the highest mountains, the beautiful wild flowers, all speak to us of the absolute gift that the Father pours into the generation of the Son. Everything created is the icon of this eternal relationship of love. All creation speaks of Christ, as the liturgy says, paraphrasing Saint Paul: “Now the Father’s plan is fulfilled: to make Christ the heart of the world.”
Hence we can contemplate the world and its history, even in its most ordinary and prosaic aspects, as a place of encounter with God, as a filial task entrusted to us by the Father, in Christ. In the light of the Trinity Christians know that they are “partners” with God, heirs in Christ to all things, working with Him to bring all created realities to the Father, with a deep gratitude for his gift. This is the heart of every Mass, the most authentic Eucharistic act, through which creation recovers the relationship with its origin, the Trinity.
Mary and the Trinity
Saint Josemaría once said: “I strive to reach the Trinity of heaven through that other ‘trinity’ on earth: Jesus, Mary and Joseph. They are, as it were, more accessible.” The love of the three persons in the Holy Family, their relationships of mutual self-giving, guided him in his contemplation of the Blessed Trinity; he ascended the “river” in search of it source, going from their love to the Love of loves.
Mary’s life is completely Trinitarian, a life transfigured by love. Mary receives her being, and gives it back to the Father in Christ thanks to the Holy Spirit, who is Love itself and who has covered her with his shadow (cf. Lk 1:35). Mary is a creature, a woman of Palestine, but everything in her is impregnated with the Love that is the eternal relationship between the Father and the Son. Thus Mary is the Lady of all creation and history. Everything has been entrusted to her Immaculate Heart, because no one knows the world better than she or can transform it better, through her intimate and familiar dialogue with each Person of the Trinity. With Mary we can live “in the heart of the Trinity … penetrating the Father’s heart and discovering new dimensions which can shed light on concrete situations and change them,” making Christ “the heart of the world.”
Suggested readings to go deeper into the topic:
Cathechism of the Catholic Church, nos. 232-267.
John Paul II, General audience 26 January 2000.
Benedict XVI, Angelus address 7 June 2009.
Pope Francis, Angelus address 22 May 2016.
 Benedict XVI, Enc. Spe Salvi (30 November 2007), no. 12.
 Saint Josemaría, notes taken in a family gathering, June 14, 1974 (Catequesis en América, 1974, vol. I, p. 449).
 Saint Josemaría, notes taken in a family gathering, February 9, 1975 (Catequesis en América, 1975, vol. III, p. 75).
 Francis, Apost. Exhort. Evangelii Gaudium (24 November 2013), no. 169.
 Saint Josemaría, The Way, no. 417. Cf. commentary in the critical-historical edition.
 Saint Josemaría, Christ is Passing By, no. 85.
 Saint Augustine, De Trinitate, 8.10.14.
 Francis, Audience, 27 November 2013.
 Jean Daniélou, La Trinità e il mistero dell’esistenza, Queriniana, Brescia 1989, p. 44.
 Cf. Francis, Apost. Exhort. Amoris Laetitia (19 March 2016), no. 63. Cf. Saint John Paul II, Angelus, July 7, 1998.
 Francis, Amoris Laetitia, no. 11.
 Third antiphon for eve of Day I of Week IV in the Psalter for Ordinary Time.
 Saint Josemaría, “Gathered Together in Unity,” in In Dialogue with the Lord, p. 217.
 Francis, Evangelii Gaudium, no. 283.