The Doctrine of the Trinity in Early Church History
Many people who reject the doctrine of the Trinity argue that it developed after the time of the apostles. Most critics of the Trinity point to the Council of Nicea in A.D. 325 and the Council of Constantinople in A.D. 381 as the events that introduced the doctrine of the Trinity into the church. This claim is not supported by the historical record. This can be shown by examining the writings of Christians before the Councils of Nicea and Constantinople.
Clement of Rome wrote a letter to the church at Corinth around A.D. 96. In this letter, he explains God in terms compatible with the doctrine of the Trinity. He writes, "Do we not have one God, one Christ, one Spirit of grace which was poured out on us?" (Cyril Richardson, Early Christian Fathers, New York: The Macmillan Co., 1970, p. 65). Clement also writes, "For as God lives, and as the Lord Jesus Christ lives and the Holy Spirit (on whom the elect believe and hope) . . . " (Ibid., p. 70). In addition, the Trinitarian formula of Matthew 28:19 is quoted twice in The Didache, a church manual written around A.D. 90-100.
Ignatius of Antioch wrote several letters before his death in A.D. 117. He affirmed both the humanity and deity of Jesus Christ in his letter to the Ephesians. "The source of your unity and election is genuine suffering which you undergo by the will of the Father and of Jesus Christ, our God" (Ibid., pp. 87-88). In the same letter he also writes, "There is only one physician-of flesh yet spiritual, born yet unbegotten, God incarnate, genuine life in the midst of death, sprung from Mary as well as God, first subject to suffering then beyond it-Jesus Christ our Lord" (Ibid., p. 90). In his letter to the Romans, Ignatius also refers to Jesus Christ as "our God" (Ibid., p. 103). Another early Christian named Justin wrote his First Apology about A.D. 155. In this writing, he declared that the Son is divine (Ibid., p. 285).
The doctrine of the Trinity is also implied in Athenagoras' Plea to Emperors Marcus Aurelius and Lucius Aurelius in A.D. 176-77, "The Son is in the Father and the Father in the Son by the unity and power of the Spirit" (Ibid., p. 309). Athenagoras repeats his Trinitarian position later in his Plea, "We speak of God, of the Son, his Word, and of the Holy Spirit; and we say that the Father, the Son, and the Spirit are united in power" (Ibid., p. 326).
Irenaeus of Lyons wrote his work Against Heresies in the late second century. He writes, "Christ Jesus our Lord and God and Savior and King, according to the pleasure of the invisible Father" (Ibid., p. 360). At about the same time, Tertullian argued that the Father, Son, and Holy Spirit are one God in his treatise Against Praxeas (Justo L. Gonzales, A History of Christian Thought, vol. 1, Nashville: Abingdon Press, 1970, pp. 182-183). Other early Christians also affirmed their belief in the doctrine of the Trinity, including Origen (A.D. 185-254) and Novatian of Rome (mid-third century) (Ibid., pp. 226, 242).