The doctrine of trinity teaches that the one true God of the Old Testament has in the New Testament further revealed himself in three ways of being (Persons) in his work of redemption: as the Father who is the source of all things, as the divine Word who came in flesh to reveal the Father and redeem the fallen race, and as the Holy Spirit who gives new life to the church and unites all things in heaven and earth under God’s rule.
The premises of the doctrine of the Trinity are: (1) The unity of God taught in both the Old Testament and the New Testament and, (2) The full deity of the Son and the Holy Spirit revealed in God’s final revelation, the New Testament.
A proper biblical view of the Trinity balances the concepts of unity and distinctiveness. Two errors should be avoided: (1) Tritheism which emphasizes distinctiveness of the Godhead to the point that the Trinity is seen as three separate Gods, or a Christian polytheism, (2) Unitarianism which disregards distinctiveness within the Godhead as it gives special focus to God the Father so that Christ and the Holy Spirit are relegated to less than divine categories. Both errors compromise the effectiveness and contribution of the activity of God in redemptive history.
Scripture Proof for the Trinity
The biblical concept of the Trinity developed through progressive revelation. The Old Testament consistently affirms the unity of God through such statements as “Listen, Israel: The LORD our God, the LORD is One” (Deut. 6:4). God’s oneness is stressed to warn the Israelites against the polytheism and practical atheism of their heathen neighbors.
The Old Testament also points towards the Trinitarian understanding of God. For example, God speaks of Himself in the plural (Gen. 1:26; 11:7). The Word of God is recognized as the agent of creation (Psa. 33:6, 9), revelation, and salvation (Psa. 107:20). The Spirit is spoken of as a distinct Person (Isa. 48:16; 63:10).
The Trinity becomes clearer in the New Testament through God’s redemptive history. The Father sends the Son into the world, and with the Son send the Holy Spirit. The Trinitarian formula registers a distinctive contribution of each person of the Godhead. (Matt. 28:19; 2 Cor. 13:14; 1 Pet. 1:2; Rev. 1:4–6)
Matthew 28:19 – The Trinitarian formula of “Father, Son and Holy Spirit” affirms the distinctiveness of each Person of the Godhead and their unity (note the singular, ‘name’).
2 Cor. 13:14 – The Trinitarian formula used by Paul, “the grace of the Lord Jesus Christ, and the love of God, and the fellowship of the Holy Spirit,” reflects how the Trinity is experienced in the actual process of salvation. The salvation experienced in Christ points to its origin in the Father and its final fulfillment through the Holy Spirit.
1 Pet. 1:2 – The Trinitarian formula is an exposition of the believers’ experience of salvation – their election (foreknowledge of the Father) and redemption (the sanctifying work of the Spirit) should lead to holy living in obedience to the Son.
The Gospel of John is most explicit in showing how salvation is Trinitarian. The Father sends the Son so that we may receive eternal life and become children of God (John 3:16). And then, the Father and Son send their Spirit to dwell in us so we can experience this new life as sons (John 3:5, 7:37–39, 15:26, 16:12–15).
Only God can save sinners. The oneness of operation between the Father, Son and Holy Spirit in redemptive history testifies to the deity of the Son and Holy Spirit. God did not reveal his tri-unity by expounding his metaphysical attributes. Instead, he revealed it through the incarnation of the Son and the outpouring of the Holy Spirit. The revelation of the Trinity took place in his work of salvation, which God then explained. The fullness of God made known by his work of salvation confirms that the Godhead is not an undifferentiated solitary oneness, but a tri-unity.
It should be stress that divine “threeness” is not merely a matter of our perception or experience of God’s action in history. Threeness belongs to the eternal essence of God no less than divine oneness. While there is only one divine essence (ousia), each of the three divine persons (hypostasis) co-inhere in that one nature (tri-unity). Thus while all three persons are God, none of the three has its own essence separate from or independent of the other two. The Father, Son, and Spirit are coequal in terms of the divine essence.
Summary of the Doctrine of the Trinity
1. God is One. The God of the OT is the same God of the New Testament. His offer of salvation in the OT receives a fuller revelation in the New Testament in a way that is not different but more complete. The doctrine of the Trinity does not abandon the monotheistic faith of Israel.
2. God has three distinct ways of being in the redemptive event, yet He remains an undivided unity. The unity of God allows for the existence of personal distinctions in the divine nature, while at the same time recognizing that the divine nature is numerically and eternally one. Within the complex unity of his being, the Father, Son and Spirit, are coequal and coeternal in power and glory though functioning in a pattern in God’s work of salvation, where God the Father reveals himself and save mankind through Son and Spirit. A compromise in either the oneness of God or the threefold way of being reduces the reality of salvation.
3. The primary way of grasping the concept of the Trinity is through the threefold participation in salvation. The approach of the New Testament is not to discuss the essence of the God, but the particular aspects of the revelatory event that includes the definitive presence of the Father in the person of Jesus Christ through the Holy Spirit.
The post draws insights from various reference works, e.g., Holman Illustrated Dictionary of the Bible, New Bible Dictionary and New Dictionary of Theology.
On the lighter side – An invitation to scholars and critics: Source critics may try to uncover the documentary sources; form critics may locate the sitz im leben of oral traditions behind periscope(s) of interest; redaction critics can infer the Tendenz of redactional purpose of my post and check with me if they got it right. Finally, deconstructionist may enjoy themselves ‘identifying’ aporias and ellipses of thoughts, ‘différance’ and deferred meaning that result from the play with unstable texts. Have fun.