Ex 34: 4b-6. 8-9; PS: Dn 3, 52.56; 2 Cor 13: 11-13; Jn 3: 16-18
Ex 3:1- 15; Ps 67; Rom 8:14-17, Jn 16:12-15
The Trinity is a shining mystery: "As only three, each is contained in the other, so that there is only one light, given the intimate interpenetration" (St. John Damascene). The revelation of the Most Holy Trinity is summarized in a simple and profound way in the short phrase from the First Letter of St. John: "God is love." God is so not only in relation to us or to the created Universe. He is so in himself, in his intimacy, essentially, infinitely, eternally. On the other hand, love is truly itself in the relationship with another that constitute it. To be charity, love must lean towards another (St. Gregory the Great).
1) To live is living together.
There are two fundamental mysteries of the Christian faith: the Unity and Trinity of God and the incarnation, passion, death and resurrection of Jesus Christ.
However, despite the importance that the Trinity has for our faith, we often have the impression that for many it is nothing more than a truth to be believed, a completely incomprehensible mystery about which we should not ask many questions.
The Trinity is a dogma that can be perceived far away and not affecting our life. Instead, it is the revelation of the secret of life, of wisdom about life, death and love. It affirms: at the beginning of all there is the bond of freedom that is communion of love.
One God in three persons: God is not solitude but communion, the ocean of his being vibrates with an infinite movement of love, reciprocity, exchange, encounter, family and celebration. When "at the beginning” God says, "Let us make man in our image and likeness", the image he speaks about is not that of the Creator, neither the one of the Spirit, nor the one of the eternal Word of God, but it is all of these things together.
In front of the revelation of the Trinity not only silence, but also wonder and joy are required because this is indeed a reality inaccessible and infinitely greater than we are, but it is at the same time a shining reality. Man himself is all lit up by it in the mind and in the heart, in contemplation and in action.
This revelation is done not to satisfy our need to know God; it directly affects the destiny of man and creation. Salvation, as a communion of love of God and of man, reflects the characters of the two entities that constitute it: God and man. Man cannot be understood without starting from God, he is made in God's image and modeled on Christ, the perfect image of God (Col 1:15). The questions and the answers about God are of fundamental importance to understand man.
In knowing the Father (The Lover), the Son (the Beloved) and the Spirit (love), we catch a glimpse that, in his innermost being, God is a dialogue, a life of love among the three Persons. This is the originality of the Christian conception of God, and it is here that man finds the true explanation of himself. Man feels an irrepressible yearning for community, solidarity and dialogue; he needs it to live and grow, he needs it more than the air. But it is only in the light of the Trinity that this finding acquires an unexpected depth: we are meant to meet, to dialogue and to love, because we are "image of God", and God is, in fact - as far as we are given to understand - a community of love.
2) Life is love.
The vocation to community is the trace of the Trinity in man. “If we see love, we see the Trinity" (St. Augustine). Pope Emeritus Benedict XVI explains: "The Spirit, in fact, is that interior power which harmonizes the hearts of the believers with Christ's heart and moves them to love their brethren as Christ loved them "(Letter Enc. Deus Caritas Est, n. 19). The Spirit immerses us in the rhythm of divine life, which is a life of love, making us personally in relations between the Father and the Son. It is not without significance that when Paul lists the fruits of the Spirit, puts love in the first place: "The fruit of the Spirit is love, joy, peace, etc...” (Gal 5:22). And since by definition love unites, this means first of all that the Spirit is the creator of communion within the Christian community, as we say at the beginning of Mass "... the communion of the Holy Spirit [i.e. the one that is made by him] be with you all "(2 Cor 13:13). On the other hand, it is also true that the Spirit stimulates us to engage in relationships of charity with all men. Therefore, when we love we make room for the Spirit, we allow him to be fully manifested.
The texts of today's liturgy, in fact, draw our attention not so much on the Mystery of the Three Persons, but on the reality of love that is contained in this first and supreme Mystery of our faith. The Father, the Son and the Holy Spirit are one because they are love and love is the absolute life-giving power. Unity created by love is more than a unit purely physical. The Father gives everything to the Son; the Son receives everything from the Father with gratitude; and the Holy Spirit is like the fruit of this mutual love of the Father and the Son.
The passage taken today from the Gospel of St. John, makes us reflect and contemplate the amazing depth and gratuitousness of the love of the Father who gives us the Son. He in his becoming flesh touches man in his concrete reality and in whatever situation he finds himself. God took the human condition to heal it from all that separates it from him and to allow us to call Him, in his only-begotten Son, with the name "Abba, Father" and be truly children of God. St. Irenaeus says: "This is why the Word became man, and the Son of God, Son of man: so that man, by entering into communion with the Word and thus receiving divine filiation, might become son of God "(Adversus Haereses, 3,19,1: PG 7.939).
The Word of God becomes flesh not for a legal requirement, but for a free requirement of love, thanks to an overabundance of love. The Trinity is nothing more than this superabundant mystery of love that has been poured out from heaven on the earth beyond all borders and all boundaries. God gives us the gift of his beloved Son, but let’s not forget that it is a gift for everyone and for the entire world.
And that's why, again in today's Gospel, St. John goes on to say that God has sent his Son to save the world, not to judge it. But the fact remains that the presence of the gift leads to a crisis: the gift of the Father can be accepted or rejected.
3) Life is to welcome Life.
What is our vocation? To live the life of the Trinity: there is no other vocation than this. Each of us is called to live the life of God and the life of God is the Holy Trinity. Our vocation is this. It is not to teach, to do a job, to work in the house or to look after the children. Our vocation is not even the simple prayer. Our vocation is God himself, to be in Him, to live Him. Our vocation calls us to this: to believe in love, to accept it, to live it.
Who, at least once in the day, does not make the sign of the cross or doesn’t recite the Lord's Prayer? These are signs which indicate our natural belonging to God, who wants to make us divine like him. The Saints had well understood that, living their own life embodying the model of Trinitarian love along the roads of the world, such as S. Francis of Assisi in poverty, St. Pius of Pietrelcina in a paternal way, Mother Teresa of Calcutta in charity, St. Therese of Lisieux secretly behind the grates of a cloistered monastery, and the Martins, the parents of the Saint of Lisieux, in the family.
Among all the Saints shines the Virgi n Mary, the creature closest to the Holy Trinity: daughter of the Father, Mother of the Son, Spouse of the Holy Spirit. The Virgin Mary, in her docile humility, has become the humble servant of Love. She has been able to accept the will of the Father, thus conceiving the Son by the Holy Spirit. In her, the Almighty, has been able to build a temple worthy of Him, making her the model and the image of the Church, the house of communion for every man and woman.
May Mary, mirror of the Trinity, help us to grow in faith and to welcome into our lives the Trinitarian mystery, a mystery that speaks of love, acceptance and communion.
May the Consecrated Virgin be an example for us. They in the everyday life guard the call to holiness through a simple life with a "profane” job. With their style of life they make Christ present everyday so to transform the world according to the Heart of God -Trinity. These women do this especially through the practice of the evangelical recommendations. In fact, "The consecrated life is thus called constantly to deepen the gift of the evangelical counsels with a love which grows ever more genuine and strong in the Trinitarian dimension: love for Christ, which leads to closeness with him; love for the Holy Spirit, who opens our hearts to his inspiration; love for the Father, the first origin and supreme goal of the consecrated life. The consecrated life thus becomes a confession and a sign of the Trinity, whose mystery is held up to the Church as the model and source of every form of Christian life "(St. John Paul II, Apostolic exhortation. Post-Synodal Consecrated Life, n. 21)
St. Athanasius' first letter to Serapion (Ep. 1 ad Serapionem 28-30: PG 26, 594-95.
"It will not be out of place to consider the ancient tradition, teaching and faith of the Catholic Church, which was revealed by the Lord, proclaimed by the apostles and guarded by the fathers. For upon this faith the Church is built, and if anyone were to lapse from it, he would no longer be a Christian either in fact or in name.
We acknowledge the Trinity, holy and perfect, to consist of the Father, the Son and the Holy Spirit. In this Trinity there is no intrusion of any alien element or of anything from outside, nor is the Trinity a blend of creative and created being. It is a wholly creative and energizing reality, self-consistent and undivided in its active power, for the Father makes all things through the Word and in the Holy Spirit, and in this way the unity of the holy Trinity is preserved. Accordingly, in the Church, one God is preached, one God who is above all things and through all things and in all things. God is above all things as Father, for he is principle and source; he is through all things through the Word; and he is in all things in the Holy Spirit.
Writing to the Corinthians about spiritual matters, Paul traces all reality back to one God, the Father, saying: Now there are varieties of gifts, but the same Spirit; and varieties of service, but the same Lord; and there are varieties of service but the same Lord; and there are varieties of working, but it is the same God who inspires them all in everyone.
Even the gifts that the Spirit dispenses to individuals are given by the Father through the Word. For all that belongs to the Father belongs also to the Son, and so the graces given by the Son in the Spirit are true gifts of the Father. Similarly, when the Spirit dwells in us, the Word who bestows the Spirit is in us too, and the Father is present in the Word. This is the meaning of the text: My Father and I will come to him and make our home with him. For where the light is, there also is the radiance; and where the radiance is, there too are its power and its resplendent grace.
This is also Paul's teaching in his second letter to the Corinthians (2:13): The grace of our Lord Jesus Christ and the love of God and the fellowship of the Holy Spirit be with you all. For grace and the gift of the Trinity are given by the Father through the Son in the Holy Spirit. Just as grace is given from the Father through the Son, so there could be no communication of the gift to us except in the Holy Spirit. But when we share in the Spirit, we possess the love of the Father, the grace of the Son and the fellowship of the Spirit himself." Saint Athanasius, Bishop of Alexandria
 The mystery of the Trinity is the foundation of the Christian faith, and yet, paradoxically, although the faith of the early Christians had already been Trinitarian (cf. Mt 28:16 and 1 Corinthians), the term Trinity appears only at the end of the second century A. C. with Theophilus of Antioch, to indicate the mystery of God who is at once One and revealed in three persons: Father, Son and Holy Spirit.
 St. Augustine writes evocatively in his "De Trinitate," "God the Father, in thinking, generates his own inner wisdom, or Word. But it is above all a relationship of love that binds the thinking mind to his Logos. So, if you seecharity, you see the Trinity. The Father is unreservedly infinite donation, the Son is active receiving, and the Spirit is the perfect unity of the one who gives and the one who receives. They are three: the Lover, the Beloved, Love. "
 We can never be grateful enough to Augustine to have set his speech on the Trinity on the word of John: "God is love" (1 Jn 4:10). God is love for this reason, Augustine concludes, he is Trinity! "Love implies one who loves, the object of love and love itself" -In the Trinity the Father is the one who loves, the source and the beginning of all things; the Son is the one who is loved; the Holy Spirit is the love with which they love each other
"The Word became flesh" (Jn 1:14). Here the word "flesh", according to the Hebrew usage, shows a man in full but just from the aspect of his transience and temporality, his poverty and contingency.