Historically speaking, “Trinity” is a term Christians use to describe the unique nature of the God of the Bible. While the Bible attests that there is only one God in essence (Deuteronomy 6:4), each particular person of the Trinity (the Father, the Son, and the Holy Spirit) is referred to as being fully God (John 1:1, 14; 8:58; Acts 5:3-4).
As advocates for historical Trinitarian theology, we recognize that no definition of God is satisfactory. He cannot be comprehensively categorized or detailed. The orthodox idea of the Trinity protects that mystery, defending the coexisting biblical realities concerning God (one in nature, plural in persons, equal in Godhood, and diverse in roles). Heresies have sought the opposite by aggressively defining the nature and relationship of the Godhead. In the orthodox spirit, we protect the paradoxical nature of the Trinity by offering the following three denials and affirmations.
First, we deny that God is one in person and that the Father, Son and Holy Spirit are merely expressions or modes of His eternal Being. The simultaneous presence of all three of the Holy Persons at Christ’s baptism undermines this modalistic thinking. We affirm that all three Persons are coexistent and coeternal.
Second, we deny that the Son or the Spirit might be considered lesser or subsidiary in nature. While the particular redemptive roles of the Trinity vary, we affirm that they are eternally coequal.
Third, we deny that the Father, the Son, and the Holy Spirit are completely separate deities. This violates the very fabric of our monotheistic faith. We affirm that there is only one God, who is forever revealed in three persons.
Occasionally, some argue that the Trinity is a fabrication of the Roman Catholic Church. Though the doctrines behind the concept of the Trinity were recognized since the earliest believers, the doctrine of the Trinity was fleshed out by ecumenical councils. Formal assertions were documented in 325 AD (the Council of Nicaea), with further clarity added in 381 AD (the Council of Constantinople). During the time of these councils, the Roman Catholic Church, as we now know it, had not been formally organized.
It is because of the doctrine of the Trinity that God can redeem us. Only an understanding of the Trinity can enable us to grasp how God can demand a payment for sin and yet also pay what He demands. In short, God the Son paid our debt to God the Father thus securing our redemption through the power of God the Holy Spirit.