What are the main Trinitarian heresies?

I. Overview of the Trinity in Scripture

The teaching that there is one God who exists eternally in three Persons—Father, Son, and Holy Spirit—emerges from a variety of Scriptures. For instance:

• “In the beginning was the Word, and the Word was with God, and the Word was God.” (John 1:1)

• “Go therefore and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit.” (Matthew 28:19)

• “May the grace of the Lord Jesus Christ, and the love of God, and the fellowship of the Holy Spirit be with you all.” (2 Corinthians 13:14)

From the earliest centuries, believers grappled with deviations from this foundational tri-personal confession. These deviations, or “heresies,” often arose from attempts to make the Triune nature of God more understandable by limiting or denying aspects of the biblical revelation.

II. Arianism

Arianism is among the most pivotal historical challenges to the Trinity. Named after the fourth-century teacher Arius, this view taught that the Son was created, having a beginning in time, and thus was not co-eternal with the Father.

1. Key Argument of Arianism: Arius reasoned that since the Son is “begotten,” He cannot be as eternal or as divine as the Father.

2. Biblical Refutation:

• “In the beginning was the Word … the Word was God.” (John 1:1) underscores that the Son (the Word) has the same divine nature as the Father.

• “I and the Father are one.” (John 10:30) reveals the Son’s equality in essence with the Father.

3. Council of Nicaea (AD 325): Early Christian leaders cited numerous Scriptures and the widespread manuscript traditions to affirm the full deity of Jesus Christ. They drafted the Nicene Creed, proclaiming the Son as “begotten, not made, being of one substance with the Father.”

III. Modalism (Sabellianism)

Modalism asserts that the Father, Son, and Spirit are merely different modes or manifestations of one divine Person rather than three distinct Persons in one Godhead. Historically called Sabellianism (after Sabellius, a 3rd-century theologian), this teaching claims that God at times appears as the Father, at other times as the Son, and at yet other times as the Spirit.

1. Key Argument of Modalism: The one God changes masks or roles. Proponents point to verses where Jesus speaks of unity with the Father to argue for a single Person adopting multiple forms.

2. Biblical Refutation:

• In the baptism of Jesus, the Father speaks from heaven, the Spirit descends like a dove, and Jesus is in the water (Matthew 3:16–17). Three are manifest simultaneously, not as shifting modes.

• “I will ask the Father, and He will give you another Advocate to be with you forever—the Spirit of truth.” (John 14:16–17). All three Persons interact relationally, which cannot be the case in mere “modes.”

IV. Tritheism

Tritheism is the belief that the Father, Son, and Holy Spirit are three independent gods rather than one eternal Being. This view fragments the single essence of God into three separate deities.

1. Key Argument of Tritheism: Advocates point to the distinct personhood of Father, Son, and Holy Spirit to claim three separate beings.

2. Biblical Refutation:

• “The LORD our God, the LORD is One.” (Deuteronomy 6:4) declares the oneness of God’s essence.

• John 1:1–3 shows the Son is divine yet distinct from the Father, but never hints at separate gods.

3. Historical Note: While not as organized a movement as Arianism or Modalism, tritheistic tendencies have appeared periodically, prompting a clarion reassertion of one essence shared by three Persons.

V. Subordinationism

Subordinationism teaches that the Son and the Spirit are inferior in being or nature to the Father, though they may still be divine to a lesser degree. This is a nuanced error that can overlap with Arianism but sometimes appears in subtler forms that preserve the deity of the Son yet make Him less than the Father.

1. Key Argument of Subordinationism: Passages describing the Son’s obedience to the Father (e.g., Philippians 2:5–8) are used to claim an eternal inequality of essence.

2. Biblical Refutation:

• Obedience does not imply inferiority of nature. Scripture presents the Son’s willing submission as part of His incarnation and redemptive mission (Hebrews 10:7–9).

• “In Him all the fullness of Deity dwells bodily.” (Colossians 2:9) demonstrates that the Son shares the fullness of the divine nature, not a lesser portion.

VI. Macedonianism (Pneumatomachianism)

Macedonianism—or Pneumatomachianism—rejects the full deity of the Holy Spirit. Macedonius, a 4th-century figure, claimed the Holy Spirit was merely a power or influence rather than a co-equal, co-eternal Person alongside the Father and the Son.

1. Key Argument of Macedonianism: The Holy Spirit is seen as a force emanating from God rather than a personal entity who can be grieved (Ephesians 4:30).

2. Biblical Refutation:

• “Why has Satan filled your heart to lie to the Holy Spirit?” (Acts 5:3) implies the Spirit is personal, given that one cannot lie to a mere force. The next verse calls the Spirit “God” (Acts 5:4).

• “The Counselor, the Holy Spirit … will teach you all things.” (John 14:26). Teaching is a personal action, underscoring personality and deity.

VII. Partialism

Partialism is the idea that the Father, Son, and Holy Spirit are “parts” or “fractions” that come together to form one God, as though each Person is a piece of the divine. This reduces the full deity of each Person and undermines the truth that each is wholly God.

1. Key Argument of Partialism: Misunderstands the Divine Being as a conglomerate rather than a single essence.

2. Biblical Refutation:

• “He is the radiance of His glory and the exact representation of His nature.” (Hebrews 1:3). The Son is fully divine, not merely a fraction of God.

• Each Person is fully God rather than a portion of divine essence (John 20:28, where Thomas calls Jesus “My Lord and my God!”).

VIII. Nestorianism (Christological Concern but Affects Trinitarian Doctrine)

Nestorianism technically deals with how Christ’s divine and human natures relate, yet it touches Trinitarian discussions by suggesting Christ’s human nature and divine nature are almost two persons. If taken to extremes, it can disrupt the unity of the Son’s Person.

1. Key Argument of Nestorianism: Christ’s two natures are so separate that He is effectively two persons—one human and one divine.

2. Biblical Refutation:

• “And the Word became flesh and dwelled among us…” (John 1:14) indicates one Person, fully divine, fully human, not two persons.

3. Council of Ephesus (AD 431): This council affirmed that Jesus is one Person with two natures, upholding the unified Person of the Son in the Godhead.

IX. Apollinarianism (Another Christological Concern)

Apollinarianism taught that Christ’s divine nature replaced or overshadowed part of His human nature, resulting in a partial human. While this is primarily a Christological heresy, any teaching that distorts the full humanity or divinity of the Son disrupts the Triune understanding by compartmentalizing the Son’s being.

1. Key Argument of Apollinaris: The divine Logos occupied the place of a human mind in Christ, so Jesus lacked a fully human nature.

2. Biblical Refutation:

• Jesus experiences hunger, fatigue, and a range of emotions (e.g., John 19:28). These require a complete human nature.

• “For in Him all the fullness of the Deity dwells bodily.” (Colossians 2:9). “All the fullness” implies truly God, yet incarnate in full humanity.

X. Historical Councils and Archaeological Support

Early Christians confronted these heresies at gatherings like the Council of Nicaea (AD 325), the Council of Constantinople (AD 381), and the Council of Chalcedon (AD 451). These councils relied on a broad network of manuscript evidence—some fragments of which (e.g., Chester Beatty Papyri, Bodmer Papyri) attest to the early acceptance of the deity of Christ and consistent references to the Father, Son, and Holy Spirit.

Moreover, early church writings (e.g., Tertullian’s use of “Trinitas” in the early 3rd century) and newly discovered archaeological manuscripts show that faithful believers upheld the unity of God’s essence while affirming the co-equality and co-eternality of the three Persons.

XI. Conclusion

The main Trinitarian heresies—Arianism, Modalism, Tritheism, Subordinationism, Macedonianism, Partialism, and certain Christological missteps (Nestorianism, Apollinarianism)—arise from attempts to rationalize a glorious mystery by diminishing one side of the biblical data.

Scripture reveals God as eternally one Being, existing in three Persons who share the same divine essence. As written: “I am the LORD, and there is no other; there is no God but Me.” (Isaiah 45:5). Yet in that one God, the Father, Son, and Holy Spirit fulfill distinct roles in creation, salvation, and ongoing relationship with humanity (Ephesians 1:3–14).

By rejecting these heresies and embracing the full breadth of biblical testimony, believers worship the true God who has revealed Himself in perfect unity of essence and distinction of Persons. This truth safeguards the heart of Scripture’s teaching on redemption: a holy Father sending a perfect Son by the power of the Holy Spirit so that salvation is fulfilled and the Triune God is glorified.