If the Trinity is of such vital important to the faith and to the Christian life, what did the testimony of the patristic fathers have to say about it? This question is asked because it is a question asked by some skeptics of the Trinity dogma. While the Faith is explained in a plain and direct manner in the first centuries, the substance of the mystery is rightly shown in the following centuries. The patristic testimony regarding the Trinity, has a definite influence on the doctrinal and liturgical life of the church now as it did then.
The work of the early church fathers can be divided in what is called Anti-Nicene and Post-Nicene. The reason for these distinctions is because the Council of Nicea was a sort of dividing line because after Nicea the dogma of the Trinity was formally defined (Preuss 142). At any rate, the first four centuries were crucial as dogma was not only defined, but even before then we see development and manifestation of the dogma in the liturgy (Garrigou-Lagrange Introduction).
At mass there are two creeds that can be said after the homily. One is the Nicean creed, and the other is the Apostle creed. The Apostles creed is only slightly older than its Nicean counterpart, but in it we profess the Trinity. Though it is made up of a few lines it declared the divinity of all three persons of the Godhead, and it is a creed that we still profess today (Preuss 144). Regarding this Garrigou-Lagrange states, “according to the arrangement of the Apostles’ Creed is the Father, the Son, and the Holy Ghost and those things attributed to them in the order of salvation” (Garrigou-Lagrange Ch. 1).
The creed itself is an extension of the sacrament of Baptism. In Baptism, one is immersed, or water is poured on the head, three times in the name of each person of the Trinity (Lecture Notes). The Trinitarian formula of baptism has biblical roots in such places as Matthew 28, but it was carried on into the liturgy and the writings of the Fathers. Tertullian, a second century Christian writer, stated that the Trinity itself is the substance of the New Testament (Garrigou-Lagrange Ch.1).
There is also evidence of Patristic testimony in the doxologies in the early church and those in use today. As was the case with Baptism, origins of these doxologies have their roots in the Pauline epistles where St. Paul writes the earliest doxologies. The prayer that we sometimes call the “Glory Be” (Gloria Patra) today, has very ancient Christian roots (Lecture Notes). Glory be to the Father, and to the Son, and to the Holy Spirit as it was in the beginning, is now, and ever shall be. World without end, amen. This prayer reflected the publicly professed faith of the early Christians, and early Christian writers (Preuss 146). It is one of the basic prayers taught to children at an early age to teach them the dogma of the Trinity. It is one that links us today with great saints such as St. Justin Martyr, wo also was familiar with this doxology (Preuss 146).
The doctrine of the Trinity is echoed in the confessions of the early martyrs. Patristic testimony celebrated these martyrs as heroes of the faith, and in some cases the patristics were among these martyrs. These martyrs are celebrated in the liturgy on various feast days throughout the liturgical calendar. St. Polycarp was martyred in 166 A.D., and before his martyrdom he gave glory all here persons of the Trinity (Preuss 145). There were many others with St. Epipodeus and St, Euplus of Cantonia just to name a couple more. These holy martyrs died for the Trinity because it was true. Just because the dogma had not been formally defined does not mean that it had not always been taught.
Garrigou-Lagrange, Reginald. The Trinity and God the Creator. https://www.ewtn.com/library/THEOLOGY/TRINITY.HTM#05, accessed November 13, 2018.
Preuss, Arthur. The Divine Trinity. https://archive.org/details/divinetrinityad00pohlgoog, accessed November 12, 2018.