Nontrinitarianism in the context of "God the Holy Spirit"

Most Christian denominations believe the Holy Spirit, or Holy Ghost, to be the third divine Person of the Trinity, a triune god manifested as God the Father, God the Son, and God the Holy Spirit, each being God. Nontrinitarian Christians, who reject the doctrine of the Trinity, differ significantly from mainstream Christianity in their beliefs about the Holy Spirit. In Christian theology, pneumatology is the study of the Holy Spirit. Due to Christianity's historical relationship with Judaism, theologians often identify the Holy Spirit with the concept of the Ruach Hakodesh in Jewish scripture, on the theory that Jesus was expanding upon these Jewish concepts. Similar names, and ideas, include the Ruach Elohim (Spirit of God), Ruach YHWH (Spirit of Yahweh), and the Ruach Hakodesh (Holy Spirit). In the New Testament the Holy Spirit is identified with the Spirit of Christ, the Spirit of Truth, and the Paraclete (helper).

The New Testament details a close relationship between the Holy Spirit and Jesus during his earthly life and ministry. The Gospels of Matthew and Luke and the Nicene Creed state that Jesus was "conceived by the Holy Spirit, born of the Virgin Mary". The Holy Spirit descended on Jesus like a dove during his baptism, and in his Farewell Discourse after the Last Supper, Jesus promised to send the Holy Spirit to his disciples after his departure.

Unitarianism is a nontrinitarian sect of Christianity. Unitarians affirm the unitary nature of God as the singular and unique creator of the universe, believe that Jesus Christ was inspired by God in his moral teachings and that he is the savior of mankind, but he is not equal to God himself. Accordingly, Unitarians reject the Ecumenical Councils and ecumenical creeds, and sit outside traditional, mainstream Christianity.

Unitarianism was established in order to restore "primitive Christianity before later corruptions set in". Likewise, Unitarian Christians generally reject the doctrine of original sin. The churchmanship of Unitarianism may include liberal denominations or Unitarian Christian denominations that are more conservative, with the latter being known as biblical Unitarians.

The pre-existence of Christ asserts the existence of Christ prior to his incarnation as Jesus. One of the relevant Bible passages is John 1 (John 1:1–18) where, in the Trinitarian interpretation, Christ is identified with a pre-existent divine hypostasis (substantive reality) called the Logos (Koine Greek for "word" or "reason"). There are nontrinitarian views that question the aspect of personal pre-existence, the aspect of divinity, or both.

Adoptionism, closely associated with dynamic monarchianism, is an early Christian nontrinitarian theological doctrine, subsequently revived in various forms. Adoptionism is a theology about relationship, which does not affirm the virgin birth and holds that Jesus was adopted as the Son of God at his baptism, his resurrection, or his ascension. Dynamic Monarchianism does not hold Jesus’ sonship was through adoption. Dynamic monarchianism is a theology about divinity, and holds there is one God, the Father, and Jesus was a man, born of virgin birth, empowered by God’s own divinity through the Holy Spirit, and raised to unity with God, but not a pre-existent distinct divine person. How common adoptionist views were among early Christians is debated, but it appears to have been most popular in the first, second, and third centuries. Some scholars see adoptionism as the belief of the earliest followers of Jesus, based on the epistles of Paul and other early literature. However, adoptionist views sharply declined in prominence in the fourth and fifth centuries, as Church leaders condemned it as a heresy.

Gaston (2023) defines a distinction between adoptionism and dynamic monarchianism as different christologies, while being commonly conflated. Adoptionism refers to a theological position about the relationship between Jesus and the Father (I.e. that he was adopted by God), not the deity of Jesus, while Dynamic Monarchianism is a Christological position about the deity of Jesus. In Dynamic Monarchiansim, “Dynamic” refers to being empowered by the Holy Spirit, while “Monarchianism” emphasizes a single deity (i.e. the Father). Gaston writes that Dynamic Monarchianism describes a Christology that was among the earliest Christologies, held by independent Theologians and maintained within mainstream Christianity until the fourth Century. Dynamic Monarchianism held that Jesus was a miraculously conceived man who, after his resurrection, ascended to heaven and to divine authority, as opposed to being an eternal divine Person who became human. Monarchianism is in contrast to Logos christologies of the second and third century, which distinguish the Logos as another divine person distinct from the Father. Monarchianism is categorized as Modalistic (where Father and Son are different designations for the same person) or Dynamic (where only the Father is God, and Jesus was empowered by his Spirit.

Ebionites (Ancient Greek: Ἐβιωναῖοι, romanized: Ebiōnaîoi, derived from Hebrew language אֶבְיוֹנִים, ʾEḇyōnīm, meaning 'the poor' or 'poor ones') as a term refers to a nontrinitarian Mosaic Law-observant Jewish-Christian sect that existed in Palestine and Transjordan during the early centuries of the Common Era.

Since historical records by the Ebionites are scarce, fragmentary and disputed, much of what is known or conjectured about them derives from the polemics of their Gentile-Christian opponents, specifically the Church Fathers—Irenaeus, Origen, Eusebius, and Epiphanius of Salamis—who saw the Ebionites as an unorthodox sect more or less distinct from other Jewish-Christian sects, such as the Nazarenes.

The doctrine of the Trinity, considered the core of Christian theology by Trinitarians, is the result of continuous exploration by the church of the biblical data, thrashed out in debate and treatises, eventually formulated at the First Council of Nicaea in AD 325 in a way they believe is consistent with the biblical witness, and further refined in later councils and writings. The most widely recognized Biblical foundations for the doctrine's formulation are in the Gospel of John, which possess ideas reflected in Platonism and Greek philosophy.

Nontrinitarianism is any of several Christian beliefs that reject the Trinitarian doctrine that God is three distinct persons in one being. Modern nontrinitarian groups views differ widely on the nature of God, Jesus, and the Holy Spirit.