What Christian Religions Do Not Believe in the Trinity: A Cross-Faith Comparison

Judaism has never accepted the Trinity doctrine, viewing it as incompatible with the strict, undivided monotheism commanded in the Torah. The Shema — 'Hear O Israel, the Lord our God, the Lord is one' — is the cornerstone of Jewish theology, and any division of the divine into persons is considered a departure from authentic monotheism. Medieval philosopher Maimonides (1138–1204) codified this in his Thirteen Principles of Faith, explicitly rejecting any corporeal or composite understanding of God.

From a Jewish perspective, non-Trinitarian Christian groups that stress the singular sovereignty of God are marginally closer to Jewish monotheism, but the veneration of Jesus as divine in any sense remains theologically unacceptable. The Hebrew Bible's repeated insistence that God alone is to be worshipped means that even a 'subordinationist' Christology — where Jesus is a created being below God — still raises serious concerns. As Deuteronomy records, the Israelites' failure to fully trust God's singular authority was itself a grave spiritual failing Deuteronomy 1:32, a warning Jewish thinkers apply broadly to theological compromise on divine unity.

Within Christianity, the Trinity — Father, Son, and Holy Spirit as one God in three co-equal persons — was formally defined at the Council of Nicaea (325 CE) and the Council of Constantinople (381 CE). However, several significant movements have rejected this formulation throughout history and into the present day. Jehovah's Witnesses, founded in the 1870s by Charles Taze Russell, teach that Jesus is a created being, the first of God's creations, and not co-equal with the Father. Oneness Pentecostals, emerging in the early 20th century, reject the three-person model entirely, insisting God is absolutely one and that 'Jesus' is the full name of that singular God. Latter-day Saints (Mormons), founded by Joseph Smith in 1830, view the Father, Son, and Holy Ghost as three distinct beings, not one substance.

The Apostle Paul's letters are frequently cited in these debates. Paul's declaration that 'Christ is all, and in all' Colossians 3:11 is read by non-Trinitarians as elevating Jesus without necessarily making him co-equal with the Father. Similarly, his statement that 'we are the circumcision, which worship God in the spirit, and rejoice in Christ Jesus' Philippians 3:3 is used to argue that true worship is directed to God through Christ, implying a distinction. Mainstream Trinitarian scholars like B.B. Warfield and more recently Michael Reeves counter that these passages presuppose rather than deny Christ's divine nature.

The stakes are high theologically. Paul warned that 'if Christ be not raised, your faith is vain' 1 Corinthians 15:17, and mainstream Christianity argues the resurrection's salvific power depends on Jesus being fully divine. Non-Trinitarian groups don't dispute the resurrection but interpret its significance differently, grounding salvation in obedience and faith rather than in the metaphysical nature of Christ's person. The early church itself was not without schism on this point — Arianism, condemned at Nicaea, taught a subordinate Christ and persisted for centuries 1 Corinthians 12:25.

It's worth noting that 'non-Trinitarian Christian' is itself a contested label. Some Trinitarian scholars argue groups like Jehovah's Witnesses or Mormons are not Christian in the classical sense precisely because they deny the Trinity, while those groups firmly self-identify as followers of Christ. The disagreement is genuine and unresolved in ecumenical dialogue.

Islam rejects the Trinity categorically and explicitly. The Quran (Surah 4:171 and Surah 5:73) directly addresses and refutes Trinitarian belief, declaring that God (Allah) is absolutely one — a concept known as Tawhid. The Prophet Muhammad (610–632 CE) taught that associating partners with God, called shirk, is the gravest possible sin. From an Islamic standpoint, all Trinitarian Christians commit shirk, while non-Trinitarian Christians who view Jesus as a prophet or a created being are considered closer to the truth, though still in error for elevating Jesus beyond his proper station as a prophet.

Islamic theology does affirm Jesus ('Isa) as a prophet, the Messiah, and a word from God — born of a virgin — but insists he was a human messenger, not divine. The Quran states that Jesus himself called people to worship God alone. Non-Trinitarian Christian groups that subordinate Jesus to God, such as Jehovah's Witnesses, would be viewed by Muslim scholars like Ibn Taymiyyah (1263–1328) as having partially recovered a truth that Islam holds completely. However, Islam's insistence that the Quran is the final, uncorrupted revelation means no Christian denomination, Trinitarian or not, is considered to have the complete picture. The New Testament's own internal tensions — such as John 3:18's emphasis on belief 'in the name of the only begotten Son of God' John 3:18 — are cited by Muslim scholars as evidence of later theological corruption of an originally monotheistic message.