Trinity

The Trinity is the Christian teaching that the one God is eternally Father, Son, and Holy Spirit — three distinct persons who share one divine being, not three gods and not one person wearing three masks. The word itself does not occur in Scripture; historically, it is a piece of church vocabulary (Greek trias, Latin trinitas, used in this sense from the early third century, notably by Tertullian) coined to summarise patterns the biblical writers assume rather than define.

The text says, on the one hand, that God is one — "Hear, Israel: Yahweh is our God. Yahweh is one" (Deuteronomy 6:4) — and, on the other, it repeatedly speaks of the Father, the Son and the Spirit together in the same breath and in the same saving action. First Peter 1:2 addresses believers "according to the foreknowledge of God the Father, in sanctification of the Spirit, that you may obey Jesus Christ and be sprinkled with his blood." Titus 3:5–6 says God saved us "through the washing of regeneration and renewing by the Holy Spirit, whom he poured out on us richly through Jesus Christ our Savior." Hebrews 9:14 speaks of Christ who "through the eternal Spirit offered himself without defect to God," and Romans 8:11 of "the Spirit of him who raised up Jesus from the dead" dwelling in believers. The servant songs carry the same note: "I have put my Spirit on him" (Isaiah 42:1), and "The Lord Yahweh's Spirit is on me, because Yahweh has anointed me" (Isaiah 61:1), words Luke 4:18 places on Jesus' own lips. John 7:39 adds a temporal dimension, noting the Spirit "was not yet given, because Jesus wasn't yet glorified." The baptismal formula of Matthew 28:19 and the benediction of 2 Corinthians 13:14 name all three in a single breath. None of these passages states the doctrine in formal terms; they are the material later reflection worked from.

Historically, the doctrine took conciliar shape at Nicaea (325) and Constantinople (381), which confessed the Son and the Spirit as fully divine with the Father, using the non-biblical vocabulary of one essence (ousia) and three persons (hypostases), and the term homoousios, "of the same being." The distinctions were defined as relational — the Father unbegotten, the Son begotten, the Spirit proceeding — in deliberate exclusion of three positions later labelled heresies: modalism (one person in successive modes), Arianism (the Son as a creature), and tritheism (three separate deities). The Athanasian Creed and the creeds of the Reformation churches restate this grammar; the word "mystery" is used in the tradition not as a refusal to think but as a limit on what the concepts can deliver.

Traditions read and weight the doctrine differently. Eastern Orthodox theology stresses the Father as the sole source or monarchia of the other two persons, treats the Latin addition of filioque ("and the Son") to the creed as an unauthorised change, and distinguishes God's unknowable essence from his communicated energies. Roman Catholic and most Protestant churches confess the filioque, and Western theology after Augustine has often used analogies from human mind and love; Reformed, Lutheran and Anglican dogmatics retain the conciliar grammar while differing over how speculative it should be. Pentecostal and charismatic theology tends to begin from the Spirit's experienced work rather than from the immanent relations. Some bodies reject the doctrine outright — Unitarianism, Jehovah's Witnesses, Oneness Pentecostalism, which is modalist in shape, and the Latter-day Saints, who hold the three to be distinct beings — and trinitarian churches accordingly do not regard those positions as the same faith. One way to read the doctrinal history is as the church's attempt to say no more and no less than the scriptural language required; whether the conciliar formulas succeed at that is itself a live question among theologians.

AI-generated reference entry, grounded in the passages where this term appears — history and Scripture stated as such, interpretation labeled as interpretation. Not a substitute for the text itself.