
The Triune Nature of God and the Deity of Christ
Jack Kettler
Introduction
It is uncommon to encounter a rejection of the Christian doctrine of the Trinity that rests on an accurate articulation of the doctrine itself. Such rejection without comprehension indicates a failure to engage the position under consideration. When an individual cannot state an opposing view with precision, that individual has not yet understood it. A frequent ground for denying the triune nature of God is the claim that the doctrine is incomprehensible. Yet if God is infinite and human beings are finite, it should occasion no surprise that the divine being cannot be exhaustively comprehended by creatures. Were God wholly comprehensible to finite minds, God would be reduced to a finite entity.
C. S. Lewis observed on this point:
“If Christianity were something we were making up, of course we would make it easier. But it is not. We cannot compete in simplicity with people who are inventing religions. How could we? We are dealing with fact. Of course anyone can be simple if he doesn’t have any facts to bother about.”1
The inability to grasp reality in its entirety does not provide sufficient grounds for rejecting it. Few people have a comprehensive understanding of the physiological processes by which their own brains function; yet this limitation does not lead them to reject the existence or reliability of their cognitive faculties. In this respect, many critics function as rationalists, treating autonomous human reason as the ultimate criterion of truth. For the Christian, however, the Scriptures constitute the ultimate standard of truth. Rejecting rationalism as an epistemological norm does not entail irrationality; on the contrary, Christian belief in the Trinity proceeds from submission to divine revelation.
Epistemologically, knowledge may be approached through empiricism (which locates the source of knowledge exclusively in sensory experience), rationalism (which appeals to the autonomous exercise of human reason), or scriptural presuppositionalism (which holds that all knowledge is contained within and deduced from a foundational system of truth, in the Christian case, the Bible). The Christian begins with the presupposition that Scripture is the self-attesting Word of God.
The triune nature of God may be expressed in three concise propositions:
1. There is only one God.
2. There are three equally divine, distinct, and eternal persons who are each called God.
3. These three equally divine and eternal persons are the one God.
Louis Berkhof articulates the doctrine with greater precision:
“There is in the Divine Being but one indivisible essence; in this one Divine Being there are three persons or individual subsistences, Father, Son, and Holy Spirit; the whole undivided essence of God belongs equally to each of the three persons; the subsistence and operation of the three persons in the divine Being is marked by a certain definite order; there are certain personal attributes by which the three persons are distinguished.”
“The Father is not the Son, the Son is not the Father, the Son is not the Spirit, and the Father is not the Spirit. The doctrine does not affirm that God is one person manifesting himself in three modes, nor that there exist three gods united merely in purpose. Rather, there is one God in essence who subsists eternally as three distinct divine persons: Father, Son, and Holy Spirit.”2
The Westminster Confession of Faith summarizes the matter with confessional clarity:
“In the unity of the Godhead there are three persons, of one substance, power and eternity; God the Father, God the Son, and God the Holy Ghost. The Father is of none, neither begotten nor proceeding; the Son is eternally begotten of the Father; the Holy Ghost eternally proceeding from the Father and the Son.”3
Scriptural Demonstration of the Triune Godhead
The biblical text attests a plurality of persons within the one Godhead. Passages that present more than one divine person acting or speaking include Genesis 1:26; 3:22; 11:7; Isaiah 6:8; 48:16; 61:1–2; Jeremiah 23:5–6; Zechariah 10:12; Matthew 28:19; Luke 4:18–19; John 1:1–3; 14:23; 2 Corinthians 13:14; Colossians 2:2; Hebrews 1:8–10; 3:7–11; 1 Peter 1:2; and 1 John 2:24.
At the same time, Scripture unequivocally affirms the oneness of God:
· “Hear, O Israel: The LORD our God is one LORD.” (Deuteronomy 6:4)
· “I am he: before me there was no God formed, neither shall there be after me. I, even I, am the LORD, and beside me there is no savior.” (Isaiah 43:10)
· “I am the first, and I am the last; and beside me there is no God.” (Isaiah 44:6)
The Father is repeatedly identified as God (Romans 1:7; 1 Corinthians 1:3; 2 Corinthians 1:2). In Exodus 3:13–14, God reveals himself to Moses as “I AM” (YHWH). The compound designation “LORD God” (YHWH Elohim) in Genesis 2:4, 8 and Exodus 3:13–14 confirms that the Father bears the divine name.
The deity of the Son is attested by direct ascription:
· “But unto the Son he saith, Thy throne, O God, is for ever and ever.” (Hebrews 1:8)
· “For in him dwelleth all the fulness of the Godhead bodily.” (Colossians 2:9)
· “This is the true God, and eternal life.” (1 John 5:20)
· “Looking for that blessed hope, and the glorious appearing of the great God and our Savior Jesus Christ.” (Titus 2:13)
Jesus identifies himself with the divine name revealed in Exodus 3:14:
“Jesus said unto them, Verily, verily, I say unto you, Before Abraham was, I am.” (John 8:58)
Greek Textual Analysis of John 8:58 and Related Passages
A detailed examination of the Greek text confirms the force of this self-identification. The Greek of John 8:58 reads: πρὶν Ἀβραὰμ γενέσθαι ἐγώ εἰμι. The phrase ἐγώ εἰμι is both emphatic (the explicit personal pronoun ἐγώ is unnecessary for the first-person verb in Greek and therefore draws attention to the speaker’s identity) and absolute (lacking any predicate nominative or complement). This construction stands in deliberate contrast to ordinary Greek usage and directly echoes the divine self-revelation in the Septuagint (LXX) of Exodus 3:14: ἐγώ εἰμι ὁ ὤν (“I am the One who is” / “I AM the Existing One”).
While the full LXX rendering includes ὁ ὤν as a translation of the Tetragrammaton’s meaning, the absolute ἐγώ εἰμι formula recurs throughout the Greek Old Testament as a marker of YHWH’s unique self-identification (cf. LXX Isaiah 43:10; 48:12). The Johannine use of the identical absolute construction, placed in the context of a claim to pre-existence before Abraham, functions as a direct appropriation of the divine name. The immediate response of the Jewish audience—taking up stones to stone Jesus for blasphemy (John 8:59)—demonstrates that they understood the statement as an assertion of deity.
Parallel absolute uses of ἐγώ εἰμι appear elsewhere in John’s Gospel (e.g., John 13:19; 18:5–6), reinforcing the pattern. In 2 Corinthians 3:17 the Greek reads: ὁ δὲ κύριος τὸ πνεῦμά ἐστιν· οὗ δὲ τὸ πνεῦμα κυρίου, ἐλευθερία. Here κύριος, the standard Septuagintal rendering of YHWH, is predicated of the Spirit, further identifying the third person of the Godhead with the divine name.
The New Testament further applies Old Testament texts concerning YHWH directly to Jesus (Isaiah 45:23 in Philippians 2:10; Psalm 68:18 in Ephesians 4:8; Jeremiah 17:10 in Revelation 2:23). Jesus’ claim, “I and my Father are one” (John 10:30), elicited the charge of blasphemy precisely because his contemporaries understood it as a claim to deity (John 10:33).
The Holy Spirit is likewise called God:
“Thou hast not lied unto men, but unto God.” (Acts 5:4, with reference to the Holy Spirit in Acts 5:3
“Know ye not that ye are the temple of God, and that the Spirit of God dwelleth in you?” (1 Corinthians 3:16)
The Spirit is presented as a personal agent capable of being lied to, of teaching, and of bringing to remembrance (John 14:26). The identification of the Spirit with YHWH appears in 2 Corinthians 3:17 (analyzed above).
All three persons participate in creation:
· The Father: “one God, the Father, of whom are all things” (1 Corinthians 8:6);
· The Son: “All things were made by him” (John 1:3; cf. Colossians 1:16);
· The Spirit: “The Spirit of God hath made me” (Job 33:4).
Each person possesses the incommunicable attributes of deity. All three are omniscient (Acts 15:18; John 21:17; 1 Corinthians 2:10), omnipotent (Revelation 19:6; Matthew 28:18; Luke 1:35, 37), omnipresent (Jeremiah 23:24; Matthew 28:20; Psalm 139:7), and eternal (Romans 16:26; Hebrews 13:8; 9:14). All three indwell believers (John 14:23; Ephesians 3:17; John 14:17) and participated in the resurrection of Christ (Galatians 1:1; John 2:19–21; 1 Peter 3:18). The simultaneous presence of the three distinct persons at the baptism of Jesus (Matthew 3:16–17) and in the Great Commission (Matthew 28:19), as well as in the apostolic benediction (2 Corinthians 13:14), demonstrates both their distinction and their unity.
Divine Titles and Functions Ascribed to Christ
The New Testament applies to Jesus Christ the divine titles and functions that the Old Testament reserves for YHWH alone.
Representative parallels include the following:
· “Creator” — Job 33:4; Isaiah 40:28; Genesis 1:1 (God) / John 1:3; Colossians 1:16; Hebrews 1:10–12 (Christ).
· “Savior” — Psalm 106:21; Isaiah 43:3; 45:21 (God) / John 4:42; Acts 4:12; 1 John 4:14 (Christ).
· “King” — Jeremiah 10:10; Isaiah 44:6 (God) / Matthew 2:1–2; Luke 23:3; John 19:21 (Christ).
· “Judge” — Genesis 18:25; Joel 3:12; Hebrews 12:23 (God) / 2 Corinthians 5:10; 2 Timothy 4:1 (Christ).
· The Great “I AM” — Exodus 3:14; Deuteronomy 32:39 (God) / John 8:58; 13:19 (Christ; see Greek analysis above).
· “Rock” — Isaiah 17:10; 2 Samuel 22:32 (God) / 1 Corinthians 10:4; 1 Peter 2:6–8 (Christ).
· “Shepherd” — Psalm 23 (God) / John 10:11; Hebrews 13:20 (Christ).
· “Light” — Isaiah 60:20; Psalm 27:1 (God) / John 1:9; 8:12 (Christ).
· “First and Last” — Isaiah 44:6; 48:12 (God) / Revelation 1:17; 22:13 (Christ).
Conclusion
The biblical data converge on a single conclusion: there is one God who eternally subsists as three distinct persons—Father, Son, and Holy Spirit—each fully possessing the divine essence.
Norman Geisler summarizes the shared attributes and the distinct personal operations:
“All three persons are omnipresent, omniscient, omnipotent, holy, eternal, true, Lord, everlasting, almighty, and powerful. The Father planned salvation, the Son accomplished it, and the Holy Spirit applies it. The Son submits to the Father, and the Holy Spirit glorifies the Son.”4
“The mathematical objection that “1 + 1 + 1 = 3” misrepresents the doctrine. The triunity of God is more accurately conceived as 1 × 1 × 1 = 1. God is triune, not triplex; his single essence subsists in three centers of personhood. There is therefore no greater mathematical difficulty in affirming the Trinity than in affirming that one cubed equals one.”5
The Westminster Larger Catechism articulates the same truth with precision (Questions 8–11), and John Calvin, citing Gregory of Nazianzus, underscores the mystery that simultaneously preserves unity and distinction:
“I cannot think on the one without quickly being encircled by the splendor of the three; nor can I discern the three without being straightway carried back to the one.”6
Consequently, the Christian confession remains: there is one God, and he is triune in nature.
“To God only wise, be glory through Jesus Christ forever. Amen.” (Romans 16:27)
Notes
1. C. S. Lewis, “Mere Christianity” (New York: Macmillan, 1952), 129.
2. Louis Berkhof, “Systematic Theology” (Grand Rapids: Eerdmans, 1979), 87–89.
3. Westminster Confession of Faith, II.3 (1646).
4. Norman L. Geisler, “Baker Encyclopedia of Christian Apologetics” (Grand Rapids: Baker, 1999), 731–732.
5. Ibid., 732.
6. John Calvin, “Institutes of the Christian Religion”, trans. Ford Lewis Battles, ed. John T. McNeill (Philadelphia: Westminster Press, 1960), 1.13.17 (slightly adapted).
Declaration
“For transparency, I note that I used Grok, an AI tool developed by xAI, and Grammarly AI for editorial assistance in drafting, organizing, and refining the manuscript’s clarity and grammar, as indicated in the article’s attribution. All theological arguments, exegesis, and interpretations are my own, and I take full responsibility for the content.” – Jack Kettler








