Is the word 'Trinity' in the Bible?

The term itself does not appear in scripture; it was coined (Latin trinitas, by Tertullian) to summarize the biblical pattern of speaking of Father, Son, and Spirit as together the one God.

What is perichoresis?

Perichoresis, or circumincession, is the mutual indwelling or interpenetration of the three divine persons, used to express how they share one life and being without losing their distinctness.

The Trinity and Divine Persons

The doctrine of the Trinity holds that the one God exists eternally as three distinct but consubstantial persons: Father, Son, and Holy Spirit.

Definition

The Christian teaching that God is one in being yet three in person, the Father, Son, and Holy Spirit, each fully God.

Scope

This topic examines the formulation of trinitarian doctrine at Nicaea and Constantinople, the technical vocabulary (ousia/substance, hypostasis/person, perichoresis, processions, and relations of origin), the distinction between the immanent and economic Trinity, and the principal models (Augustinian psychological, Cappadocian social, and modern relational accounts). It treats the filioque dispute and contemporary social trinitarianism. The presentation is descriptive, laying out the doctrine and its interpretations rather than defending its truth.

Core questions

How can God be one substance and three persons without contradiction?
What do the terms person, substance, and procession mean in trinitarian theology?
How are the immanent and economic Trinity related?
Does the Spirit proceed from the Father alone or from the Father and the Son?

Key theories

Psychological analogy: Augustine's account that locates trinitarian vestiges in the structure of the human mind (memory, understanding, will), modeling the unity of the persons on the unity of a single rational soul.
Social trinitarianism: A modern relational model, indebted to the Cappadocians and developed by theologians such as LaCugna, that treats the persons as a communion of distinct subjects whose mutual indwelling (perichoresis) constitutes the divine unity.

History

Arising from reflection on the New Testament's language about Father, Son, and Spirit, the doctrine was defined against Arianism at Nicaea (325) and completed at Constantinople (381). The Cappadocians distinguished one ousia in three hypostases, while Augustine's De Trinitate shaped the Western tradition. The medieval West added the filioque, a flashpoint in the schism with the East. Twentieth-century theology revived the Trinity as a practical and central doctrine.

Debates

The filioque: Whether the Holy Spirit proceeds from the Father alone, as Eastern Orthodoxy holds, or from the Father and the Son, as the Latin West affirms, a difference of both doctrine and ecclesial authority over the creed.
Social versus relational models and the charge of tritheism: Whether social trinitarian models adequately preserve divine unity or risk dividing God into three gods, against which critics defend more unitive Augustinian or simplicity-based accounts.

Key figures

Athanasius
The Cappadocian Fathers
Augustine of Hippo
Karl Rahner
Catherine LaCugna

Seminal works

augustineTrin
rahner1970
lacugna1991

Frequently asked questions

Is the word 'Trinity' in the Bible?: The term itself does not appear in scripture; it was coined (Latin trinitas, by Tertullian) to summarize the biblical pattern of speaking of Father, Son, and Spirit as together the one God.
What is perichoresis?: Perichoresis, or circumincession, is the mutual indwelling or interpenetration of the three divine persons, used to express how they share one life and being without losing their distinctness.