The Trinity is an expression of Christian monotheism. Modern neo-Trinitarian theologians may protest that I am here assuming what needs to be proved, but the response is simply that this series is an explanation of the historic meaning. If one wishes to contest this meaning, then that is their privilege, but they will then assume the burden of showing why their formulation can use the traditional signifiers while disagreeing with the traditional things signified. For now, we explain the faith.
The Trinity is One God. The Biblical support for this is found in Deut. 6:4 and James 2:19 (among other NT passages). At no point does the Bible apply the term “gods” to the Creator, nor does it suggest that any other heavenly beings are equal with Him. The Nicene Creed sates “We believe in one God.” The pseudo-Athanasian Creed states, “That we worship one God in Trinity, and Trinity in Unity” and “they are not three Gods, but one God. ” The 39 Articles state, “There is but one living and true God.” The Heidelberg Catechism takes monotheism for granted, wishing to know how the confession of 3 persons does not contradict it. It answers, “these three distinct persons are the one only true and eternal God” (Q&A 25). The Westminster Confession of Faith mostly echoes the 39 Articles and adds to them, retaining monotheism at the very beginning of its discussion, “There is but one only living and true God…”
If the Trinity were not supposed to be an expression of Monotheism, many of the early church debates would have been less pressing. Arius had no trouble attributing some notion of deity to Jesus. He was simply unwilling to confess a shared substance between the Father and the Son. The Homoiousions and Homoians likewise wished to affirm a general notion of deity to the Son, but were unwilling to confess a total identity of the divine nature in both God the Father and God the Son. Athanasius, famously, was unwilling to compromise even on the “one iota.” There had to be homoousios. But why this burden if not for monotheism? Even Gregory of Nyssa, often appealed to by neo-Trinitarians, affirmed that the Trinity was monotheism. He went so far as to write a treatise called “On Not Three Gods.”
One can find the occasional Christian mystic attempting to describe his faith as distinct from both monotheism and polytheism, but this was almost always limited to rhetorical flourish or pietistic utterance, unusually in contrast to non-Christian forms of monotheism. Whenever a consistent explanation was required, the Christian faith was clear. The Trinity is One God. We will explore how this claim was supported in the next installment.