What is the Solemnity of the Holy Trinity?

Trinity Sunday is celebrated the first Sunday after Pentecost (in 2022, it falls on June 12). Though the mystery of the Trinity has always been central to Christianity, it was not until 1334 that Pope John XXII formally added it to the universal Church’s calendar.

What is the Trinity?

It is a mystery! But not just any mystery—the Most Holy Trinity is the “central mystery of the Christian faith and life” (CCC 234). It is so key to Christianity because the Holy Trinity is God’s revelation of himself to humanity. God is the Most Holy Trinity.

Three Persons, One God

The Most Holy Trinity is three persons (Father, Son, and Holy Spirit) in one God. This does not refer to three Gods, but rather one God with three distinct persons, each of whom is “God whole and entire” (CCC 253). This belief is woven into the celebration of the Catholic Mass in the recitation of the Nicene Creed: “I believe in one God, the Father almighty […] I believe in one Lord Jesus Christ, the Only Begotten Son of God […] I believe in the Holy Spirit, the Lord, the giver of life, who proceeds from the Father and the Son."

Jesus also makes it clear in the Gospels that there are three persons in one God when he says “Go therefore and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit” (Matthew 28:19). Jesus understands grammar; the use of the singular “name” is intentional. One God.

God the Father

God the Father is often thought of as the Creator. In calling him “Father,” we acknowledge that He is “the first origin of everything and transcendent authority” while also recognizing that He is “goodness and loving care for all his children” (CCC 239). After His Incarnation, Jesus further revealed God’s identity as the Father of His only begotten Son.

God the Son

God the Son is Jesus Christ, "the image of the invisible God” (CCC 241) and “the Word.” The Gospel of John reminds us, “In the beginning was the Word, and the Word was with God, and the Word was God” (John 1:1). Through the mystery of the Incarnation, Jesus, the eternal Word of God, took on flesh. But this changed nothing of His divinity; Jesus possesses both a divine nature and a human nature united in one person (“true God and true man”). Through the Passion, Death, and Resurrection of Jesus, God opened the way to salvation for all mankind.

God the Holy Spirit

God the Holy Spirit, also known as the “Advocate or “Paraclete,” proceeds from the love between the Father and the Son. As promised by Jesus, the Holy Spirit came to the apostles at Pentecost in a “sound like the rush of a violent wind” (Acts 2:2). The Holy Spirit is “one and equal with the Father and the Son, of the same substance and also of the same nature” (CCC 245). But the third person of the Blessed Trinity did not stop with the apostles; the Holy Spirit lives, moves, and works in the lives of all Christians.

Saints & The Holy Trinity

St. Patrick (386-461): Perhaps one of the Church’s most popular saints, St. Patrick was born in England and brought to Ireland as a slave. He escaped, only to return to Ireland as a missionary. A popular legend says that St. Patrick used the shamrock to explain the mystery of the Holy Trinity.

St. Thomas à Becket (1118-1178): Born in England, St. Thomas à Becket was consecrated as the archbishop of Canterbury on the Sunday after Pentecost. He requested and was given permission to celebrate Trinity Sunday on this day in the Church of England every year. St. Thomas à Becket protected the Church from King Henry II’s influence and was martyred in his church. He is the patron saint of diocesan clergy.

St. Elizabeth of the Trinity (1880-1906): Canonized in 2016, St. Elizabeth of the Trinity spent years catechizing in her parish before she became a Carmelite nun at the age of 21. She is known for her writings, including prayers (for example Holy Trinity, Whom I Adore) and retreats. St. Elizabeth of the Trinity referred to the Trinity as “my Three” and much of her spirituality focuses on God (the Trinity) dwelling in us. “He is always with you, be always with Him, through all your actions, in your sufferings, when your body is exhausted, remain in His sight, see Him present, living in your soul.”

Why Trinity Sunday?

If the Most Holy Trinity is God, isn’t every Sunday about God? So why do we need a special day?

The full mystery of the Trinity was revealed by God over time. The Old Testament prophets knew about God the Father and the promise of the Messiah. The Gospels tell us of Jesus’ life, death, and resurrection. Finally, at Pentecost, the Holy Spirit was sent as a guide into the world: “And see, I am sending upon you what my Father promised” (Luke 24:40).

At Christmas, we remember that God created the world and sent his only Son to earth. During Holy Week and Easter, we recall Christ’s suffering and resurrection, thus bringing about salvation for humanity. Fifty days later on Pentecost, God sends us the Holy Spirit. Trinity Sunday comes next, celebrating and bringing to mind what God has gradually revealed about himself.

If the mystery of the Most Holy Trinity has your head spinning a bit every time you try to think of it, don’t despair! A wise parish priest once said, “The Trinity is a mystery to behold, not to be solved.” The catechism assures us this mystery is true. The revelation of the mystery of the Most Holy Trinity is a gift from God. He wants us to know Him! Trinity Sunday is the perfect opportunity to spend time reflecting on the mystery of the Holy Trinity and trying our best to know God more deeply.