I. Lexical Definitions
To thoroughly understand the biblical usage of terms describing Deity and divine unity, it is necessary to examine authoritative lexical definitions of One, Oneness, Only, Unify, Union, and Unity.
1. ONE
Adjective: * Single; undivided, united; the same; a certain unspecified time (Webster’s Dictionary, p. 373).
Being a single individual or object; being a unit.
Being an individual or thing thought of as indefinite.
Designating a person, thing, or group as contrasted with another; this; that.
Single in kind; the same; closely united or alike.
Unitary (Funk & Wagnalls Standard Dictionary, Vol. 2, p. 883).
Noun: The first and lowest cardinal number; an individual thing or person (Webster’s Dictionary, p. 373).
Pronoun: An indefinite person; used to apply to many people; someone (Webster’s Dictionary, p. 373).
2. ONENESS
Noun: * Individuality, singleness, unity (Webster’s Thesaurus, p. 686).
Agreement, concord.
Quality of being unique (Funk & Wagnalls, Vol. 2, p. 883).
3. ONLY
Adjective: Alone of its kind; single, sole; standing alone by reason of excellence (Webster’s Dictionary, p. 373; Funk & Wagnalls, p. 883).
Adverb: Solely, merely, just, not more than; exclusively; limiting a statement to a single defined person, thing, or number.
Conjunction: Except that, but.
4. UNIFY
Verb (transitive): To make into one; to unite; unification (Webster’s Dictionary, p. 536).
5. UNION
Noun: The act of uniting, or the state of being united; a combination of several things; a confederation of individuals or groups; the joining of two persons in marriage (Funk & Wagnalls, Vol. 2, p. 1372).
6. UNITY
Noun: * Oneness; harmony; concord; state of existing as essentially one (Funk & Wagnalls, p. 1372).
(Mathematics) The number or numeral one; a quantity assuming the value of one.
(Dramatic Arts) Classical and neoclassical principles requiring a single plot (unity of action), restricted location (unity of place), and events within a single day (unity of time) (Aristotle’s Poetics; Webster’s Dictionary, p. 536).
II. Biblical Affirmations: “There Is One God”
Scripture firmly establishes that there is only one true God:
Deuteronomy 6:4: “Hear, O Israel: The LORD our God, the LORD is one!”
Galatians 3:20: “Now a mediator does not mediate for one only, but God is one.”
1 Timothy 2:5: “For there is one God and one Mediator between God and men, the Man Christ Jesus.”
James 2:19: “You believe that there is one God. You do well. Even the demons believe—and tremble!”
III. Scriptural Evidence: Plural Items or Persons Counted as “One”
Throughout the Old and New Testaments, the word “one” (Hebrew: Echad; Greek: Heis, Hen, Henos, Heni, Hena) frequently modifies a plurality of individuals, elements, or entities joined in corporate unity, harmony, or shared nature:
Old Testament
Genesis 2:24: Two (husband and wife) become “one (echad) flesh” in marital covenant.
Ezekiel 37:16, 19: Two distinct sticks are joined into “one (echad) stick.”
Ezekiel 37:22: Two divided kingdoms (Judah and Israel) become “one (echad) nation.”
Malachi 2:15: Husband and wife are made “one” by God.
Gospel Accounts
Matthew 19:5–6 & Mark 10:8: Two distinct persons become “one flesh” in their unity.
Luke 14:18: Multiple invited guests made excuses with “one accord” (mian).
John 10:30: Jesus declared, “I and My Father are one (hen)”—affirming their shared divine nature, power, and purpose.
John 17:11, 21–23: Believers are prayed to be “one (hen)” just as the Father and the Son are “one.”
Acts & Epistles
Acts 17:26: God made from “one (henos) blood” all nations of mankind.
Acts 23:6: A diverse council/assembly is addressed as one unit.
Romans 12:4–5: Many members form “one (heni / hen) body” in Christ.
Romans 15:6: Believers glorify God with “one (hena) mind and one mouth.”
1 Corinthians 3:8: “He who plants and he who waters are one (hen)” in ministry purpose.
1 Corinthians 6:16–17: A man joined to a harlot becomes “one (hen) body,” while he who is joined to the Lord is “one (hen) spirit.”
1 Corinthians 10:17: “Though we are many, we are one (heis) loaf and one (hen) body.”
1 Corinthians 12:12: The body is “one (hen)” and has many members, yet all members of that “one (henos)” body form “one (hen)” body.
Galatians 3:28: “You are all one (heis) in Christ Jesus.”
Ephesians 2:14–16: Christ broke down the wall of separation between Jews and Gentiles to make the two “one (hen)”, creating “one (hena) new man” in “one (heni) body.”
Hebrews 2:11: Both the Sanctifier and those being sanctified are “all of one (henos).”
IV. The Theological and Hermeneutical Scope of “One” and “Only”
Critics from unitarian positions (such as Islamic apologists or INC-1914 debaters) often operate on the rigid assumption that numbers can only describe isolated, single mathematical units. However, lexical and scriptural analysis demonstrates two key principles:
1. The Principle of Compound Oneness (Inclusivity)
The word “one” (hen / echad) is routinely used as a collective or unifying adjective denoting sameness of class, unity of nature, harmony of will, and organic union. Just as a husband and wife are “one flesh” without losing their distinct personal identities, the Father, Son, and Holy Spirit are One God—sharing the exact same divine essence, attributes, omniscience, omnipotence, and eternal purpose.
2. The Contextual Meaning of “Only” (Uniqueness vs. Absolute Exclusion)
The word “only” (yachid in Hebrew; monogenes or adverbial monon in Greek) does not always function as a strict mathematical boundary that excludes all others:
The Isaac Precedent (Genesis 22:2, 12, 16; Hebrews 11:17):
God calls Isaac Abraham’s “only son” (yachid). Yet, Genesis 16:15 explicitly confirms that Ishmael was also Abraham’s son. Isaac is designated “only” not because Ishmael did not exist, but because Isaac held an exalted, unique position as the promised covenantal heir.
Application to John 17:3:
When Jesus prays to the Father as “the only true God,” the modifier “only” exalts the Father’s uncreated divine nature above all false, created idols. It does not strip deity from the Son or the Holy Spirit, who elsewhere share the Father’s eternal pre-existence, glory, and divine titles (cf. Isaiah 9:6; John 1:1–3; John 20:28; Romans 9:5; Philippians 2:5–7; Titus 2:13; Hebrews 1:5–8; 2 Peter 1:1).
Application to Passage Emphases (”Only Believe”):
In passages like Mark 5:36 and Luke 8:50 (”Only believe”), the term highlights the immediate, paramount requirement of the moment; it does not exclude repentance, love, or ongoing obedience in the total biblical pattern of salvation.
V. Conclusion
When biblical texts use terms like “ONE” or “ONLY,” sound hermeneutics requires that we examine the full counsel of Scripture. Where other passages explicitly reveal distinct Persons sharing the exact same divine nature, the word “one” describes unity and sameness of essence, not mathematical isolation. The Triune God is truly One—a perfect unity of Father, Son, and Holy Spirit.
— Eusebio A. Tanicala, Ph.D. / Word Ministry