As we celebrate the Solemnity of the Most Holy Trinity, we need to consider the evidence of what is seen and what is not seen in order to penetrate the mystery of the Trinity. We need both reason and faith. Sacred Scripture both records for us what has been seen in the course of history and reveals to us what is hidden behind the visible events of history. Scripture records the events of creation, redemption and sanctification. Hidden within these events of history is the presence of the Holy Trinity, the Father who created all things (heaven and earth, all that is seen and unseen), the Son who redeemed the world through his self-gift, his oblation of love, his sacrifice on the cross and the Holy Spirit who sanctifies the world through his purifying fire of love, his power to forgive sins and the truth that is spoken through the prophets and allows us to live in the freedom of the children of God.

In order to claim to know someone we must certainly, at the very least, know that person’s name. When someone reveals their name to us it is an invitation to a more personal, intimate relationship with that person. “What can I call you?” we ask of someone who we wish to befriend. In the history of salvation recorded in Scripture, the friends of God have asked to know his name. In chapter 34 of Exodus we are told that “the Lord stood with Moses there and proclaimed his name, “Lord.” Okay, that’s a beginning. God is “Lord.” This doesn’t yet reveal the fullness of the mystery of the Holy Trinity. In the gospel of John, Thomas makes a profession of faith and names Jesus, “My Lord and my God.” “Jesus is Lord,” is one of the oldest professions of faith of the early Christian community. St. Paul will proclaim to us in his letter to the Corinthians, “No one can say Jesus is Lord except through the Holy Spirit.” (1 Cor 12,3) Thus, the name of God, “Lord,” is only known through the Father, the Son and the Holy Spirit.

In the gospel of John, St. John also helps us to name the mystery of God. In his letter to the Church he tells us simply that “God is love.” God reveals that he is love by the sending of his Son Jesus into the world to save the world. Jesus promises to send the Spirit to continue his work of love and salvation. We know the love of God by the gifts he has sent us in his Son and the Spirit.

Pope Benedict wrote about the mystery of the Trinity, “On this Sunday that follows Pentecost, we are celebrating the Solemnity of the Most Holy Trinity. Thanks to the Holy Spirit, who helps us understand Jesus’ words and guides us to the whole truth (cf. Jn 14: 26; 16: 13), believers can experience, so to speak, the intimacy of God himself, discovering that he is not infinite solitude but communion of light and love, life given and received in an eternal dialogue between the Father and the Son in the Holy Spirit – Lover, Loved and Love, to echo St Augustine. In this world no one can see God, but he has made himself known so that, with the Apostle John, we can affirm: “God is love” (I Jn 4: 8, 16), and “we have come to know and to believe in the love God has for us” (Encyclical Deus Caritas Est, n. 1; cf. I Jn 4: 16). Those who encounter Christ and enter into a friendly relationship with him welcome into their hearts Trinitarian Communion itself, in accordance with Jesus’ promise to his disciples: “If a man loves me, he will keep my word, and my Father will love him, and we will come to him and make our home with him” (Jn 14: 23).”

Pope John Paul II wrote, “When we approach the mystery of the Holy Trinity, we are clearly aware that we find ourselves before the first of those “mysteries hidden in God which, unless they are divinely revealed, cannot be known” (First Vatican Council, DS 3015).The entire development of divine revelation is directed to the manifestation of God-Love, of God-Communion. This concerns, first of all, the Trinitarian life considered in itself, in the perfect communion that for all eternity unites the three divine Persons: the Father, the Son and the Holy Spirit. By revealing his love to man, God calls men to share his own life and to enter into communion with him. To the universal vocation of believers to holiness, each of the three divine Persons makes his own specific contribution: the Father is the source of all holiness, the Son is the mediator of all salvation and the Holy Spirit is the One who animates and sustains the journey of man towards full and definitive communion with God.”

The facts that God’s love has been seen and has manifested itself in many different ways through the Father, Son and Holy Spirit and the witness of faith that has pointed us to the mystery of Trinitarian life and communion helps us to know the truth of God’s love for us. There is one God, one Lord, one Love that is expressed in the three persons of the Trinity, each person unique in how they reveal that love, living in an eternal relationship of unity and communion.