Study Guide: Doctrine of the Trinity
(Use this study guide for deeper study of sermon preached on May 18, 2025)
The word “doctrine” refers to the body of teachings or beliefs that are considered authoritative and foundational to the Christian faith. These teachings are based on the Bible and help guide the beliefs and practices of Christ followers. Doctrines are essential for maintaining the integrity of the Christian faith and they help to ensure unity among believers because they reflect the core truths of Christianity.
The doctrine of the Trinity is central to the Christian faith, representing unity and diversity within the nature of God. The Trinity teaches that God exists as three distinct persons—Father, Son, and Holy Spirit—yet remains one in essence. In Matthew 28:19, Jesus commands His followers to baptize "in the name of the Father and of the Son and of the Holy Spirit," emphasizing the distinct roles and unity of the three persons of the Godhead. This foundational doctrine affirms that God is not divided, but exists as a perfect community of love, power, and purpose.
Each person of the Trinity plays a unique role in our salvation and daily lives. The Father, as the Creator and sustainer of all, is the source of all that is good and the planner of redemption (John 3:16). The Son, Jesus Christ, fulfills God’s plan by becoming incarnate, living a sinless life, and offering His sacrifice on the cross for our salvation (John 1:14). Finally, the Holy Spirit empowers believers, teaching, convicting, and guiding us into all truth (John 14:26). Without any one of these persons, our understanding of God would be incomplete, and the fullness of salvation would be lacking.
The doctrine of the Trinity is not just a theological concept but a practical truth that shapes how we live and relate to God. It teaches us about the nature of love and unity, because the three persons of the Trinity live in perfect harmony and mutual submission. As believers, we are invited into that divine fellowship and called to reflect the love and unity seen in the Trinity in our relationships with others (1 John 4:7-8). Understanding the Trinity helps us worship God in truth, live in the power of the Holy Spirit, and grow in a deeper, more intimate relationship with the Father and the Son.
Study Outline
Take some time to look up and read these verses in your Bible, highlight, or spend time reflecting as you read.
1. The Oneness of God
The Bible clearly teaches that there is only one God.
Deuteronomy 6:4 – "Hear, O Israel: The Lord our God, the Lord is one."
Isaiah 44:6 – "Thus says the Lord, the King of Israel, and his Redeemer, the Lord of hosts: 'I am the first and I am the last; besides me there is no god.'"
1 Corinthians 8:6 – "Yet for us there is one God, the Father, from whom are all things and for whom we exist."
2. The Three Persons of the Trinity
A. God the Father
John 6:27 – "For on him God the Father has set his seal."
1 Corinthians 8:6 – "Yet for us there is one God, the Father, from whom are all things and for whom we exist."
B. God the Son (Jesus Christ)
John 1:1, 14 – "In the beginning was the Word, and the Word was with God, and the Word was God... And the Word became flesh and dwelt among us."
John 10:30 – "I and the Father are one."
Colossians 2:9 – "For in him the whole fullness of deity dwells bodily."
Hebrews 1:3 – "He is the radiance of the glory of God and the exact imprint of his nature."
C. God the Holy Spirit
Acts 5:3-4 – Peter refers to lying to the Holy Spirit as lying to God.
John 14:16-17 – Jesus calls the Holy Spirit "another Helper" and "the Spirit of truth."
2 Corinthians 3:17 – "Now the Lord is the Spirit, and where the Spirit of the Lord is, there is freedom."
3. The Three-in-One Relationship
Though distinct in personhood, the Father, Son, and Holy Spirit are united as one God.
Matthew 28:19 – "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."
2 Corinthians 13:14 – "The grace of the Lord Jesus Christ and the love of God and the fellowship of the Holy Spirit be with you all."
John 14:26 – "But the Helper, the Holy Spirit, whom the Father will send in my name, he will teach you all things."
4. Analogies for Understanding the Trinity
While no analogy perfectly captures the mystery of the Trinity, these word pictures can help illustrate the concept:
Water Analogy – Water exists as liquid, ice, and vapor but remains H2O.
Family Analogy – A father, mother, and child are distinct persons but part of one family.
Sun Analogy – The sun has light, heat, and energy, yet is one entity.
5. Common Misunderstandings and Heresies
Modalism – The belief that God is one person who manifests in different modes (e.g., Father in the Old Testament, Son in the New Testament, and Spirit today). This denies the distinct personhood of the Trinity.
Arianism – The belief that Jesus is not fully God but a created being. Refuted by John 1:1 and Colossians 2:9.
Tritheism – The belief that the Father, Son, and Holy Spirit are three separate gods, contradicting Deuteronomy 6:4.
6. Why the Trinity Matters
Salvation – Each person of the Trinity is involved in salvation: The Father plans (Ephesians 1:4-5), the Son redeems (Ephesians 1:7), and the Spirit seals (Ephesians 1:13-14).
Prayer – Christians pray to the Father (Matthew 6:9), in the name of the Son (John 14:13-14), by the power of the Holy Spirit (Romans 8:26-27).
Christian Unity – The unity of the Trinity serves as a model for Christian relationships (John 17:21).
DISCUSSION QUESTIONS:
The following questions can be used for personal reflection, small group discussions, Bible studies, or for journaling.
How would you explain the doctrine of the Trinity to someone unfamiliar with Christianity?
Why is it important to emphasize both the oneness and the three persons of God?
How do Deuteronomy 6:4 and Matthew 28:19 work together to support the doctrine of the Trinity?
What are some key Bible passages that show Jesus is fully God? How do they refute the idea that He is merely a created being?
How does understanding the Trinity impact your personal faith and worship?
In what ways does the Trinity serve as a model for Christian unity and relationships?
Why is Modalism incorrect, and how does it misunderstand the nature of God?
What are the dangers of denying the Trinity, and how might it affect one’s understanding of salvation?
Which analogy (e.g., water, sun, family) helps you best understand the Trinity, and why?