Part of my dissertation deals with the usefulness of Revelation for Trinitarian theology, with some of the major Church Fathers as part of my justification. So, over the past few weeks, I’ve been reading the early church’s use of the Book of Revelation in their discussions on the divinity of the Father, Son, and Holy Spirit.
As I’ve been working through the development of early Trinitarian language, I’ve identified what I consider three stages of development:
1. Incipient Trinitarianism (ca. AD 30-96)
This stage happened between the resurrection of Jesus and the end of the writings of the biblical canon. In the case of John or Paul, for example, the language for the Trinitarian persons is not systematized or always terminologically consistent. However, the biblical writers clearly understood that their view of monotheism needed to be reimagined in light of Jesus’s resurrection and the sending of the Holy Spirit. This can be seen in biblical authors’ tying Jesus and the Spirit to the identity of YHWH in the OT through titles, exegesis of passages, doxologies, and logical explanations. See, for example, John 1:1-14; 1 Cor 8:6; 1 Pet 1:2; Rev 1:4-18.
2. Proto-Trinitarianism (ca. AD 96-325)
This stage of Trinitarianism refers to the post-biblical era which stood as a precursor to the Nicene/Nicene-Constantinopolitan creeds. This type of Trinitarianism begins to deal with the ingredients provided by biblical-canonical data. Similar to Incipient Trinitarianism, this is not a fully systematized doctrine of the Trinity, but it is more advanced because writers in the period began to grapple with the philosophical ideas of ontology and economy in God’s being. For example, Irenaeus and Origen’s theologies have hints of Trinitarianism, but they’re especially not precise in a later creedal sense about how God is both one in essence and three in personhood.
3. Nicene-Constantinopolitan Trinitarianism (ca. AD 325-381)
This stage of Trinitarianism is the fully systematized, orthodox version that we confess today. Given the development and diversity of early Christian theologies of the Father, Son, and Spirit, these councils/creeds gave precise language to the biblical data in a way that preserved orthodoxy for the future of the church and weeded out the philosophical hoop-jumping of early heretics.
In an article I published with the Criswell Theological Review, I conflated the terms “incipient” and “proto-” (among other things I’d like to change, but such is publishing life). I like this taxonomy better, given the standard definitions of the terms. This could change one day, too, but this type of framing seems to be a helpful way to categorize the stages of early Trinitarianism.
 Michael Bird uses a similar taxonomy, though he applies both the “incipient” and “proto-“ categories to biblical texts in order to demonstrate a level of diversity within the biblical data itself; Cf. Michael F. Bird, Evangelical Theology (Grand Rapids: Zondervan Academic, 2015), 106-13.