The solemnity of the Most Holy Trinity is ancient. The
origins of the solemnity can be traced to the seventh
century. It has been on the Church's universal calendar for
nearly seven hundred years. "The central mystery of
Christian faith and life" is the mystery of the Most Blessed
Trinity (CCC, 234 - Click Here to read more).
This solemnity offers us time to meditate
upon this defining mystery of our faith.
This is also the first of the three doctrinal feasts
celebrated after Pentecost, which commemorate not a
person but a theological tenet, doctrine, or devotion.
Today’s solemnity celebrates the doctrine of the Triune
God, one God in three divine persons - Father, Son, and
Holy Spirit.
In the fourth century, the Church underwent a serious
crisis when Arius, a priest of Alexandria, denied the
divinity of Christ, and as a consequence, faith in the
Trinity and the equality of the three divine Persons. The
heresy, called Arianism, was condemned by the councils
of Nicaea (325) and Constantinople (381). The result
was the formulation of the Creed that we recite at Mass
today.
In celebration of the Eucharist, notice how frequently
we articulate our belief in the Trinity: with the sign of the
Cross, the Doxology at the end of the presidential
prayers, the Gloria, the Profession of Faith, and the
Eucharistic Prayer culminating in the Great Doxology
above, and finally with the Solemn Blessing at the end of
Mass.
The stained glass window is from St. Thomas the Apostle Church in Bloomfield, NJ.