Updated: Jul 12
“And this is life eternal, that they should know thee the only true God, and him whom thou didst send, even Jesus Christ.” John 17:3
We' can safely say that this text is one of the most bulletproof texts in monotheistic thought. A Unitarian prooftext like no other.  This is a unitary foundational text that gives us insight into the theology of Jesus that circulated the Hebraic cultural milieu in the 1st century.
This chapter accentuates Jesus’ high priestly prayer of request and worship, thus provides us with insight as to
1. What is eternal life
2. Who is in a (definite) restricted category, the-Only True God.
3. Who was sent on who's behalf, courtesy of THE ONLY TRUE GOD”.
When prayer is present in the scriptures one doesn't have to expect a cohesive story as to a novel. For we have a God who hears prayers wherever and whomever we are with. Jesus prayed with not only His words, but with his testimony. This is highly significant for us because it's a viable alternative to how we should live our daily lives. Jesus lays out a foundation as to how we should pray and that is evident in this text of exclusion. 
How do you get non-exclu from μόνον [only]?
Thesis: In John 17:3, Jesus excludes himself from the category One true God by the use of the continuative conjunction "καὶ" (and),  also, Jesus uses two other terms that exclude him from also being true God, as the Father is God and those are, the use of the singular personal pronoun "σε" (you) and the singular adjective "μόνον" (only). To suggest this doesn't exclude others would forge a subset proposition, it is not a subset proposition. The subset proposition is where the S (subject) is a classified subgroup of the PN (predicate nominative). That is the subject belongs to a specific class or faction and is not substantial. The subset semantic is the more raw way of explaining a relationship that does not imply indistinguishability.  Moreover, Jesus utilized a definite usage -σε τὸν μόνον ἀληθινὸν θεόν.. τὸν μόνον/Ton Monon (the only/ one) implies strict exclusion;  i.e if one was to say Christ is the μόνος man who died for our sins we would not make this an invitation to include others.
Impossibile from the grammar
Saying that the Father is the only true God, and the Son along with the Holy Spirit according to John 17:3 is virtually impossible from a grammatical and contextual point of view. In Greek, “you, the only true God,” is a convertible proposition. Daniel Wallace insightfully notes; "this construction indicates an identical exchange. That is to say, both nouns have an identical referent. The mathematical formulas of A=B, B=A are applicable in such instances. 
Because both terms are definite. The Father is the only true God and the only true God is the Father. The pronoun σε has the same referent as τὸν μόνον ἀληθινὸν θεὸν. That exhausts the title “only true God” to the God that is prayed to. It also results in an identical exchange to "only the Father is the only true God”. Also, as mentioned earlier, notice the definite article (τὸν/the). This implies a separation of class, and a pointer to definitize.  It modifies the adjectives μόνον ἀληθινὸν because they are describing an attribute or quality of the direct object (σὲ). Since it is in the attributive position according to Greek grammar, this in climax means that the Father is the only one ‘alone’ with the qualities of true deity. σε is a 2nd Person singular/ Possessive Pronoun in the Accusative case, which means [σε/You] is the direct object of a transitive verb. That in turn means it’s directly pointing to the Father. There are also predicate nominations formed from nominations in simple apposition. You/thee (the Father) = the subject and the only true God = predicate nominative are interchangeable. 
Since grammatically it is shown to be a convertible proposition, that is to say, a predicate nominative formed from two nominations in simple apposition, creating an exhausted title "the only true God” leaves no room for ambiguity. Thus the subject (σὲ) and predicate nominative (τὸν μόνον ἀληθινὸν Θεον) becomes a convertible semantic. The two constructions are identical with an S-PN semantic and two questions are settled. Who is the Father? (the known entity) & who is the only true God? (the same entity). There is only one possible antecedent to these questions. Ironically, this clause that Trinitarianism dismiss seems to bite back with a theological significant force. There are unwarranted arguments formulated by Trinitarians who suggest the relevant clause (17:3) is implicitly that of a subset.  To my knowledge, no one has given a sufficient contextual nor grammatical argument to substantiate as to why.
Does the adjective modify the adjective in relation to θεὸν?
There exist another complicated grammatical argument proposed by the Trinitarian grammar enthusiastic apologists that entails the modification of the noun θεὸν has an anaphoric relation to the adjectives μόνον ἀληθινὸν (only true). That the adjective μόνον modifies ἀληθινὸν θεὸν only establishes Monotheism that expresses one God in a general sense. This argument is short-handed and is simply special pleading with the linguistics. In Greek, and is the case with most languages and grammar, adjectives do not modify adjectives by definition. Adverbs modify adjectives if used in conjunction. An exception would be the use of a compound adjective, i.e. a dark-brown horse. Even so, it is not in modification. In general, the singular noun θεὸν is only being modified by ἀληθινὸν. However, Jesus reveals to us that the antecedent to the accusative σέ (there, you) points directly to God the Father alone. This seems to cancel out a broad statement of monotheistic supremacy. To restrict the entire proposition by using snippets of factoids here and there is lazy exegesis. The Father is mentioned as the lone subject to the predicate ἀληθινὸν θεὸν. The adjective-noun combo describes God identically. This is an emphatic proposition as we will explore later in this article.
The category of ἀληθινὸν θεὸν (true God) is not open in Jesus’ priestley devotion because the antecedent or subject, Πάτερ (Father) in verse one is the only possible option …This would respectively exclude Jesus himself as a shareholder within this same true God. There is only one true θεός. Jesus here doesn't claim to also be True God nor does he mention a 3rd party as a possibility. For Jesus, the Father is indeed τὸν μόνον ἀληθινὸν θεὸν, that is, a predicate contingently related to the subject - The "God who is alone true". We have the greatest example of humility, submission to the highest degree, and anti-self-glorification in this text by our Lord Jesus Christ. Also, θεον is not merely a subset category, it does not have a flexible enough semantic to introduce the possibility of another subject . Thistour the trinitarian dilemma when they appeal to the μονον-θεον association. They make αληθινον θεον elastic and nonunique, thus the possibility of multiple Gods.
John 17:3 and it's relation to just false God’s
The saying goes “When the Lord Jesus said the only true God He wasn‘t denying that He was God but that the Father is the only true God in relation to false gods” 
Introducing the notion of ―God in contrast with idols in no way weakens a Unitarian stance. It‘s a case of special pleading, even a red herring, to introduce this notion and have this passage mean anything else based on this idea, since this was not remotely even the presupposition against which Jesus said this prayer. But, even if he did (which is unlikely he didn't), it would still corroborate the Proto-Hebriac understanding of biblical monotheism, which Biblical Unitarianism accurately stands for. A simple textual analysis and cognitive linguistics would have us conclude that the speaker identifies His Father, someone distinct and separate from Jesus himself as "The” (definite) “ONLY” (exclusive) “TRUE” (none fictitious) GOD (identity). It's also important to note that “One” implies a contrast with more than one of something. This by default would include the Trinitarian position that Jesus and the HS (assumed as a distinct person) are not incorporated into the proposition. 
A proclaimed neutralizing text to falsify this conclusion
John 17:5 is often used by Trinitarian apologist as a misdirection text.  The text, although in the same chapter has no real association to vs 3 notwithstanding being in the same chapter. One text is an affirmation of the salvific idea of knowing who is alone true deity, the other is a subordinate act of asking for something from a Superior. However, looking at the passage zoomed out we can see the context is in the form of a prayer, subordinates don’t make commands nor is consider equal to the recipients in prayer to superiors. It usually connotes one who is not deity making supplication to someone who is deity. This was a simple prophetic request to receive glory he had before the world was preordained to happen (aka fait accompli). Nevertheless, it may have been delegated. [See Psalm 84:11]. We see a striking parellel in Matthew 25:34 where the kingdom of God was prophetically prepared before the world’s creation and is ready for possession. The author notes "Then shall the King say unto them on his right hand, Come, ye blessed of my Father, inherit the kingdom prepared for you from the foundation of the world". See also Luke 24:25-26.
An argument was made that the imperative mode implies Jesus has some type of divine authority to demand his glory from God the Father. The imperative mode is unsupportive to a multi-personal God view that consists of total consubstantiality between all parties. The fact that δόξασόν is in the "imperative mode” (in the aorist tense) in conjunction with the context suggest some form of subordination. Ironically there are a few in the "Jesus is God” camps who continue to erroneously attempt to push up this claim as Jesus making some type of demand as an equal authority. Conversely, the imperative mood/mode doesn’t express only command (order) or demand, it also expresses a request, entreaty, or desire from a subordinate to a superior. 
παρὰ + dative?
There is another more complex objection to a unitarian reading in this text. That the dative accompanied by the preposition παρὰ (para) - “with”, suggest only a person to person relationship in close proximity.  But this is misleading, the proposition in of itself is not an absolute rule, it is only a logical tendency in the grammar of the NT. Logical tendencies are not syntactical therefore are open to other suggestions. It is simply not true that the dative + para only works for literal people in close proximity, we see things also described as an abstraction will suffice as well. Consider John 19:25…Thayer’s Lexicon notes: “para...II. With the DATIVE, para indicates that something in the immediate vicinity of or (metaphorically in his mind), nearby, beside, in the power of, in the presence of, with,...i.e. in one’s town; in one society;...”
John 19:25 reads “These things, therefore, the soldiers did. But there were standing by the cross of Jesus”. The construction παρὰ τῷ (standing by) would be a para + dative case used to describe things done near the cross. There is no indication that person to person close proximity is required with the dative modified by the preposition παρά.
Another attempt to falsify the Unitarian position is the claim that the adjective μόνον (only) modifies ἀληθινὸν (true)… This is indefensible because adjectives never modify adjectives. Furthermore the construction is attributive, that is the adjective qualifies the noun (θεὸν), hence modifying it in a class. Thus θεὸν is in a class of one.
Wallace points this out in his GGBB; "When the article is present, the relation of adjective to noun is easy to determine. When the adjective is within the article-noun group (i.e., when it has an article immediately before it), it is attributive to the noun and hence modifies or qualifies the noun in some way. When the adjective is outside the article-noun group, it is predicate to the noun and hence makes an assertion about it.
Jude 4 comparison
Concerning Jude 4, I contend the word Κύριον has more flexibility than the title "ἀληθινὸν Θεὸν" true God. The way Jude uses it seems to be relative. That is, yes Jesus is our only Lord and Master in the sense of his redemptive work, the anointed one sent on behalf of his God (that is mentioned in the same text). No, the Father is not the Lord to the same capacity as Jesus but is indeed The Lord of us and Jesus in an absolute sense. This is similar to how Abraham can be called the Father of the Jews while simultaneously acknowledging YHWH as the Father par excellence. 
Having glory with God is merely a declaration about glory in expectation. If we continue to read down to verse 20 it speaks about Christ Jesus is praying for future believers that are not literally in existence yet. Then he proceeds in vs 22 to say “the glory which You gave Me I have given them”, thus we see a summation of how Christ had a promised glory in the mind of God before the beginning. If we can confess that the lamb was be slain since before the beginning (Rev.13:8) we can likewise say Christ’s glory, as a result (Heb.3:3), would be predestined to be manifested in reality.
Peter says something similar "having been foreknown indeed before the foundation of the world, but having been revealed in the last times for the sake of you" (1 Peter 1:20). Figures of speech are a matter of abstraction. The wooden literal approach is inconsistent with how figures of speech work. A preexisting abstraction in the mind of God is not a novice idea in pre-second temple and post-second temple Judaism. In Talmudic tradition, the rabbis believed that repentance, the Garden of Eden, the Throne of Glory, the Temple, and the name of the Messiah were created before the world. The idea of a plan is obviously at play here, without needing to be explicitly stated. 
Wisdom of Solomon. A 1st century B.C. text, which depicts platonic influence (as Holding notes), describes Solomon as offering the following prayer: “As a child I was by nature well endowed, and a good soul fell to my lot; or rather, being good, I entered an undefiled body.” (8:19-20)13
Testament (Assumption) of Moses. In this 1st century A.D. text Moses says: “But he did design and devise me, who (was) prepared from the beginning of the world, to be the mediator of his covenant.” (1:14)
II Enoch. This text (perhaps first century A.D.) reflecting Jewish ideas states that “all the souls are prepared for eternity, before the composition of the earth.” (23:5)18; Also see Eph 1:3-6, 2:6, Gal 1:15-16 & Jer 1:5, All speaks about a notional pre-existence by means of God's foreknowledge and planning.
Whatever glory that God had given Jesus and whenever God gave it to him can only be fully understood in the context of verse 22. The Christ tells us that he had given believers that same glory, and the effect of the glory is that we can be one - as the Christ is one with God.
The two phrases that ultimately lead to confusion here.
1. Before the world was/existed
2. Glory - what is this glory?
We see the idea of 'before the world was' elsewhere in scripture. Peter again tells us that the Christ was prophesied through (prognosis) foreknowledge of the Father - Peter uses the same word to describe the "existence" of the Son of God in God’s plan as he did to describe the "existence" of the Christian church (v. 2).
Interesting fact: There is a perfectly decent word for "real" or literal preexistence in the Greek προ υπάρχον (pro-uparchon).
God's earthly sanctuary existing and having glory before creation: in the DDS (Dead Sea Scrolls) 11Q'P XXIX ll. 7-10: God's temple had glory and a form of preexisting state before creation;
“I shall accept them and they shall be my people and I shall be for them forever. I will dwell with them for ever and ever and will sanctify my s[an]ctuary by my glory. I will cause my glory to rest on it until the day of creation on which I shall create my sanctuary, establish- ing it for myself for all time according to the covenant which I made with Jacob in Bethel.”
Psalm 84:11 stresses that anyone who continues to walk upright will be given glory from God. "
E.C. Derrick notes in Primitive Christian Eschatology that:
“When the Jew said something was ‘predestined,’ he thought of it as already ‘existing’ in a higher sphere of life. The world’s history is thus predestined because it is already, in a sense, preexisting and consequently fixed. This typically Jewish conception of predestination may be distinguished from the Greek idea of preexistence by the predominance of the thought of ‘preexistence’ in the Divine purpose.”
The notion of an assumed preexisting messiah in the NT can also be tracked down in early pre-Christian Jewish literature. I.e J.R. Daniel Kirk mentions that 4 EZRA presents a human messiah as existing in prospect, yet created prior to coming to earth. He says; “ this Davidic and human Messiah [the son of man figure] seems to exist in heaven with God before coming to earth. This son is reserved where none can see him (13:52), but Ezra is about to go to live with him (14:9)”…(brackets mine). 
This could be an early resource behind the ideal pre-existent glory God had with his anointed human messiah that will be returned after a future exaltation in John 17:5…
God on a micro-level shares his glory
James R. Harris notes that “God glorifies his own king and protects him with his glory (δόξα Ps 3:3; 21 [LXX 20] :5-6) and, reciprocally, David worships God's glory in the sanctuary (δόξα: Ps 63 [LXX 62]:2). Thus God's glory is uniquely displayed in Israel (δόξασαν με: 1 Sam 15:30 [LXX 1 Kgs 15:30]; δοξασθήσεται: Isa 44:23) and God promises to be her eschatological glory (δοξάσαι: Isa 60:13).
Moreover, as the King of the universe, God extends his glory over the nations (δόξα: 1 Chr 16:24; Ps 96 [LXX 95]:3; 97 [LXX 96]:6; Isa 60:2-3; 66:18-19; Ezek 39:21) and throughout the entire earth (δόξα: Pss 57 [LXX 56]:5, 11; 72 [LXX 71]:19; 108 [LXX 107]:5; 113 [LXX 112]:4; Isa6:3; ἔνδοξον ἔσται: Isa24:15). God gains glory for himself (τοῖς ἐνδόξοις: Isa 26:15; M~a: 43:7; ἐνδοξασθήσομαι: Ezek 28:22) and gives his glory to no other (δόξα: Isa42:8; 48:1)” 
John 17:3 covers all bases for a Unitarian reading.
1. Traditional logic , the statement is a categorical proposition or categorical statement. That is to say ultimately, Jesus puts the Father in a class that only allows the subject “him” (speaking directly to the Father) to be the lone member. We can compare this to an identical proposition, Jesus is the only Christ, and Christ is only Jesus. There are no additional subjects outside of Jesus Christ considered due to the exhausted title that is interchangeable.
2. Grammatically it is shown to be a convertible proposition, that is to say, a predicate nominative formed from two nominations in simple apposition, creating an exhausted title “the only true God”. Thus the subject (σὲ) and predicate nominative (τὸν μόνον ἀληθινὸν θεὸν) become interchangeable.
3. Contextually the weight of evidence in the entire body of literature points to the Father as addressed as God par excellence (the highest form). See Exodus 4:22-23, Deut.32, 1Chron. 29:18, 2 Sam.7:11-22, Isa.63:16, Mal.2:10, Acts 2:36, 1Corin 8:6, Eph.1:2, 1 Tim 2:4, John 20:17 etc...
Here, in the relevant text, both nominatives have an identical referent, The Father. If 17:3 were a subset proposition it would be logically conceivable to allow for more subjects to be in the class of the only true God. It would produce either of the three, 1) state a large category, (2) be ambiguous, or (3) be metaphorical in its meaning. But this is not the case.
We must know that the only true God is the God of Jesus and that he sent him on his behalf. The “and him whom thou didst send, even Jesus Christ” is not a predication of "the only true God”. The only true God only applies to the one being spoken to (the Father) and knowledge of his Christ is essential. Similar to how the Israelites were to listen and believe the words of the prophets in the OT.
In retrospect, no one should deny God’s decree of anything. To us Unitarians, there should be or at least we don't see a hint of any ontological ramifications in that text.
 See for example Anthony Buzzard and Charles F. Hunting’s “The Doctrine Of The Trinity: Christianity’s Self-Inflicted Wound” commentary on Jhn 17:3 pages 0, xii, xiii, 4, I , 38, 39, 68, 85, 95, 126, 133, 174, 212, 220, 236, 284, 291, 293, 294, 314, 320, 325, 329, 332, 340.
 See"Communion with God: Prayer In All It's Many Facets" by Paddick Van Zyl. pg 8
 Daniel Wallace comments that “This use simply connects an additional element to a discussion or adds an additional idea to the train of thought. It is translated and, though if it is emphatic, it can be translated also, indicating a key addition. This latter use (also) is sometimes called adjunctive. The major connective conjunctions are καί and δέ. δέ as a connective conjunction may often be left untranslated. "The Basics of New Testament Syntax: An Intermediate Greek Grammar" by Daniel B. Wallace. Pg. 552 Zondervan, Grand Rapids, Michigan 49530
 σὲ (se) is a personal possessive pronoun - 2nd person accusative singular; μονον agrees in speech with the pronoun and is likewise an adjective - accusative singular masculine, thus the Father spoken of in verse 1 is the only possible antecedent.
 Ibid 43
 See 1 Timothy 1:17, Romans 16:27 for scriptural reference
 [Excerpt from: "The Basics of New Testament Syntax: An Intermediate Greek Grammar" by Daniel B. Wallace. pg 46 [also see his visual chart for demonstration]
 David L. Mathewson comments on the particulars of the article, “Although we maintain that the practice is misleading, discussion of ὁ, ἡ, τό as the “definite article” is not without some reason. The Greek article was indeed employed to distinguish one or more particular persons, places, or things from others. It was also variously used to point forward or back to particular items in discourse. Consequently, the Greek article can be said to fill the grammatical slot of an identifier. The basic function of the article is to point out; how it does so is capable of more than one interpretation or English translation.”; Also with the adjective, “The article may be used as a nominalizer with an adjective to mark it as substantival or to distinguish it as being in either the predicate or attributive position”…["Intermediate Greek Grammar: Syntax for Students of the New Testament" by David L. Mathewson, Published by Baker Academic, a division of Baker Publishing Group, P.O. Box 6287, Grand Rapids, MI 49516-6287 pg. 148-151]
 Wallace pg. 48
 For a common Trinitarian dogmatic interpretation see https://thebereans.net/2021/05/19/refuting-the-iglesia-ni-cristos-misinterpretation-of-john-173/
 See Marc Taylor‘s rebuttal to Danny André Dixon’s thesis on John 17:3 on “An Online Written Debate Conducted Between August 17, 2010 and October 2, 2010”, A Scholarly Debate on the Supreme Deity of God the Father: Original link http://kingdomready.org/blog/2010/08/13/announcing-a-trinity-debate/
 See “The Only True God: A Study of Biblical Monotheism” Eric H.H. Chang Copyright © 2009, 2017 for an exhaustive analysis on the term τὸν μόνον ἀληθινὸν θεὸν and Monotheism’s counterpart theological faction, Biblical Unitarianism.
 See James White & Zakir Hussain on 8/15/17 concerning John 17:3-5https://youtu.be/stiP_RxJU8o
 In many cases in ANE culture, deities are the recipients of prayer by non-deity subordinates. See “Akkadian prayers and hymns : a reader / edited by Alan Lenzi.
p. cm. — (society of Biblical Literature ancient near east monographs ; v. 3)
english and Akkadian, pg. xii) ; Alan Lenzi quotes “Each treatment begins with a succinct introduction to the entity ad- dressed or praised in the text. In most cases, this means an introduction to a deity. But in a few treatments, the addressee is undetermined or not a deity”… These would include an apparent absence of prayer to YHWH as a command in the biblical literature as well.
 Luke 24:25-26 “And he said unto them, O foolish men, and slow of heart to believe in all that the prophets have spoken! 26 Behooved it not the Christ to suffer these things, and to enter into his δόξαν (glory)?"
 See Robertson “A Grammar of the Greek New Testament, p. 320f”
 See “Definitive Look at Oneness Theology: Defending the Tri-unity of God” pg. 59
By Edward L. Dalcour
 Thayers Greek Lexicon complete entry on παρά with the dative case ; [II. with the dative, παρά indicates that something is or is done either in the immediate vicinity of someone, or (metaphorically) in his mind, near by, beside, in the power of, in the presence of, with, the Sept. for אֵצֶל (1 Kings 20:1 (); Proverbs 8:30), בְּיַד(Genesis 44:16; Numbers 31:49), בְּעֵינֵי (see b. below); cf. Winers Grammar, § 48, d., p. 394f (369); (Buttmann, 339 (291f)]
 Jhn 19:25 “εἱστήκεισαν δὲ παρὰ τῷ σταυρῷ τοῦ Ἰησοῦ ἡ μήτηρ αὐτοῦ καὶ ἡ ἀδελφὴ τῆς μητρὸς αὐτοῦ Μαρία ἡ τοῦ Κλωπᾶ καὶ Μαρία ἡ Μαγδαληνή”
 See Anthony Rodgers http://www.answeringmuslims.com/2016/08/this-is-true-god.html
 Excerpt from: "The Basics of New Testament Syntax: An Intermediate Greek Grammar" by Daniel B. Wallace.
 Interestingly, Albert Pietersma says “But since there is no sure proof that kyrios in these works is a substitute for the tetragram, we had better not draw on them. Similarly, we might appeal to Aristeas 155 which contains a near quotation of Deut 7:18, and Aristobulus who seems to make reference to Exod 9:3;31 but since these authors were transmitted by Christians, kyrios could be secondary”. https://digilander.libero.it/domingo7/Kyrios%20tetra.pdf.
 For scriptural references see Gen.17:5, Luke 1:73, 3:8, 16:24, Acts 7:2, Rom.4:16, Jam.2:21
 Pesachim 54a
 For example, Ephesians 2:6 uses two indicative verbs συνήγειρεν & συνεκάθισεν to emphasize something that will happen in the future.
 The Hulsean Prize Essay for 1908, Cambridge University Press,1912, by E.C. Derrick pp. 253, 254.
 Excerpt from: "A Man Attested by God: The Human Jesus of the Synoptic Gospels" by J. R. Daniel Kirk. pg. 246
 Paul and the Imperial Authorities at Thessalonica and Rome
A Study in the Conflict of Ideology by James R. Harris: 6.4 Paul and the Jewish Ideal of Glory, pg. 235
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