Sources and Justifications: The Argument from Eternal Relational Love

This page provides the biblical, historical, and philosophical foundations for the argument. Not every conclusion appears in Scripture as a formally stated syllogism. Some points are directly revealed, while others are philosophical conclusions drawn from those revealed truths.

The argument rests upon three kinds of support:

  1. Scripture reveals God’s eternal, unchanging, loving, and triune nature.

  2. Christian theologians explain how love, personhood, procession, and divine perfection fit together.

  3. Philosophical reasoning asks what must follow if all those truths are held consistently.

1. God Is Eternal, Perfect, and Unchanging

The argument begins with the classical Christian understanding of God. God does not grow, improve, acquire new attributes, or move from an incomplete condition into a more complete one.

Scripture

  • Psalm 90:2 teaches that God exists “from eternity to eternity.”

  • Malachi 3:6 says, “Because I, the Lord, have not changed.”

  • James 1:17 describes God as the Father of lights who does not change.

  • Hebrews 13:8 says Jesus Christ is the same yesterday, today, and forever.

  • Matthew 5:48 calls the heavenly Father perfect.

Thomas Aquinas

Aquinas argues that God is pure actuality, meaning there is no unrealized potential within Him. A changing thing moves from what it potentially is to what it actually becomes. God cannot undergo that kind of movement because there is no perfection He lacks and must later acquire.

In Summa Theologiae I, Question 4, Article 1, Aquinas says that perfection corresponds to actuality. God, as the first and most actual principle, must therefore be supremely perfect. In Question 9, Article 1, he argues that God cannot acquire anything new or reach something He had not already possessed. Aquinas, Summa Theologiae I.4.1 and I.9.1.

Justification

If love belongs to God’s nature, God does not gradually become more loving. Any form of love essential to divine perfection must exist eternally and fully within Him.

That is the foundation of the argument. God cannot begin with an incomplete form of love and later depend upon creation to supply what was missing.

2. God Does Not Merely Love. God Is Love

Scripture

The strongest biblical foundation is found in 1 John 4:7–16.

John twice states that “God is love.” He also presents love relationally:

  • Love is “from God.”

  • The Father sends the Son.

  • God’s love is revealed through the Son.

  • Believers participate in that love through communion with God and one another.

John is not simply saying that God sometimes performs loving actions. Love belongs to who God is.

Other relevant passages include:

  • John 3:35: “The Father loves the Son.”

  • John 5:20: “The Father loves the Son and shows him everything he is doing.”

  • John 17:24: The Father loved the Son before the foundation of the world.

Thomas Aquinas

Aquinas explicitly argues that love properly exists in God. Love is not a bodily passion in God, but an eternal act of His will.

He writes that love is the first movement of the will and the root of its other movements. Because will exists perfectly in God, love must also exist perfectly in Him. Aquinas, Summa Theologiae I.20.1.

Justification

Because God is eternal and God is love, love cannot be something that began when creatures appeared. Whatever it means for God to be love must already have been true before creation.

3. Self-Giving Relational Love Contains a Perfection Isolated Self-Love Does Not

Scripture does not state the sentence “relational love is greater than isolated self-love” word for word. That conclusion comes from examining how Scripture describes the fullness of love.

Scripture

  • Matthew 22:37–39 commands love for God and neighbor.

  • John 15:13 presents self-giving love for another as the greatest love.

  • 1 Corinthians 13:4–7 describes love through other-directed actions: patience, kindness, truth, endurance, and the refusal to seek only oneself.

  • 1 John 4:11–12 says God’s love reaches completion in believers loving one another.

  • Philippians 2:3–8 presents Christ’s self-giving humility as the pattern of love.

Thomas Aquinas

Aquinas defines loving another as willing the good of that person. He distinguishes self-love from love directed toward another and says that friendship requires rational beings capable of returning love and sharing life with one another. Aquinas, Summa Theologiae I.20.1–2.

Richard of St. Victor

Richard of St. Victor developed one of the clearest historical versions of the argument from love.

In On the Trinity, Book III, Richard argues that nothing is more excellent than perfect charity. But perfect charity must be directed toward another. If only one divine person existed, there could be self-love, but there could not be perfect interpersonal charity.

Richard then argues that love reaches a still greater fullness when two persons do not keep their love closed between themselves but share it with a third. This shared love is sometimes called condilectio, with the third person described as the condilectus, the co-beloved. See Richard of St. Victor, On the Trinity, III.2–5 and III.11–20. This study summarizes Richard’s argument and its primary citations.

Justification

The claim should be stated carefully. Proper self-love is not evil, and relational love does not make self-love worthless. The point is that other-directed, reciprocal, self-giving love contains something isolated self-love does not: communion with another.

If God possesses every genuine perfection fully, eternal communion cannot be completely absent from God.

4. Potential Love Is Not the Same as Actual Relational Love

A solitary person may have the ability to love another without actually sharing love with another. The capacity is real, but it is not identical to an actual relationship.

Scripture

John 17:5 and 17:24 do not describe the Father as merely possessing the potential to love the Son. Jesus speaks of actual glory and actual love shared before creation.

The Father did not begin loving the Son when the universe was created. Their relationship precedes the universe.

Thomas Aquinas

Aquinas’ distinction between potentiality and actuality supports this step. God is not waiting to become something He is not. God lacks no actuality proper to His perfection. Aquinas, Summa Theologiae I.4.1 and I.9.1.

Justification

If interpersonal love were only a future possibility for God before creation, then creation would bring about an actual relationship that did not previously exist.

The argument therefore asks whether a perfect and fully actual God can eternally possess only the ability to share love while lacking the actuality of shared divine love.

Christianity answers that God’s relational love was never merely potential. The Father eternally loved the Son.

5. God Does Not Need Creation

God did not create because He was lonely, incomplete, or dependent upon creatures.

Scripture

  • Acts 17:24–25 says God is not served as though He needed anything.

  • Psalm 50:9–12 declares that the world and everything in it already belong to God.

  • Romans 11:35–36 asks who has first given to God and concludes that all things are from Him.

  • John 17:5 speaks of the glory the Father and Son shared before the world existed.

  • Ephesians 1:4–5 presents creation and adoption as flowing from God’s gracious purpose, not His deficiency.

Thomas Aquinas

Aquinas argues that God does not will creatures by an absolute necessity of His nature. God acts through intellect and will, and the existence of creatures is not something He requires in order to be complete. Aquinas, Summa Theologiae I.19.3–4.

He later connects this directly to the Trinity. The procession of divine love shows that God creates creatures because of His goodness, not because He needs them or requires some external completion. Aquinas, Summa Theologiae I.32.1.

Justification

If creation were necessary for God to experience interpersonal love, creation would answer a deficiency in God.

The Trinity avoids that problem. God’s personal communion is already eternally complete. Creation is therefore a free expression of divine goodness, not God’s attempt to escape isolation.

6. The Hierarchy of Being and the Fullness of Personhood

The essay describes a hierarchy:

  1. Existing

  2. Living

  3. Conscious or perceptive

  4. Rational and personal

  5. Capable of free, reciprocal love

This is not an arbitrary ranking. It follows a longstanding Christian understanding of creation.

Scripture

Thomas Aquinas

Aquinas gives almost the exact hierarchy used in the essay. He says created things resemble God first by existing, then more fully by living, and still more fully by knowing and understanding. Intellectual creatures most properly bear God’s image. Aquinas, Summa Theologiae I.93.2.

He also says:

“Person signifies what is most perfect in all nature.”

Aquinas argues that personhood belongs preeminently to God because everything truly perfect must be attributed to God in the highest manner. Aquinas, Summa Theologiae I.29.3.

Justification

Personhood is not a defect that must be stripped away when speaking of God. Intellect, will, agency, and the capacity for personal love are perfections.

Therefore, the source of personal beings cannot be less than personal. God possesses the perfection of personhood in a manner infinitely greater than creatures do.

7. The Father Eternally Loves the Son

The relational distinction between Father and Son does not begin at creation.

Scripture

  • John 1:1–3 says the Word was with God, was God, and created all things.

  • John 1:18 describes the Son in intimate relation with the Father.

  • John 3:35 states that the Father loves the Son.

  • John 17:5 speaks of shared glory before the world existed.

  • John 17:24 explicitly says the Father loved the Son before the foundation of the world.

  • Colossians 1:15–17 places the Son before creation and identifies Him as the one through whom creation exists.

Basil the Great

Basil rejects the idea that the Father became Father at some later point. He says the Father is eternally Father and that the Son and Holy Spirit are eternal and divine. Basil, Letter 8.

Gregory of Nazianzus

Gregory says the Father’s begetting of the Son is without time, passion, or bodily division. The Son is eternally begotten, not created. Gregory of Nazianzus, Theological Oration 29.

Thomas Aquinas

Aquinas explains that the divine Word does not move from potentiality into actuality. The Word proceeds eternally within the same divine nature and is therefore properly called the begotten Son. Aquinas, Summa Theologiae I.27.2.

Justification

The Father was never without the Son. God did not first exist as a solitary person and later produce another being. The Father-Son relationship is eternal.

8. The Holy Spirit as Personal, Proceeding Love

The essay’s statement that the Holy Spirit is the personal fullness of divine love belongs to a major Augustinian and Thomistic tradition. It must not mean that love first existed impersonally and then created the Spirit.

The Spirit is eternal, uncreated, fully divine, and personally distinct.

Scripture

  • John 14:16–17 distinguishes the Father, Son, and “another Counselor.”

  • John 15:26 says the Spirit proceeds from the Father and is sent by the Son.

  • John 16:13–15 shows the Spirit knowing, speaking, hearing, receiving, and glorifying. These are personal acts.

  • Romans 5:5 says God’s love is poured into believers’ hearts through the Holy Spirit.

  • 2 Corinthians 13:13–14 joins Christ’s grace, God’s love, and the Spirit’s fellowship.

  • Galatians 5:22 names love as the first fruit of the Spirit.

Augustine

Augustine explores the relationship between the lover, the beloved, and love itself in On the Trinity, especially Books VIII, IX, and XV. He treats love as an analogy through which we may begin to understand the Trinity while repeatedly warning that no creaturely analogy perfectly captures God. Augustine, On the Trinity, Book IX and Book XV.

Thomas Aquinas

Aquinas says that “Love,” when understood personally, is a proper name for the Holy Spirit. Just as the Son proceeds as the divine Word, the Spirit proceeds by way of love.

Aquinas also cites Augustine’s statement that the Spirit is the one through whom the Begotten is loved by the Begetter and loves His Begetter. Aquinas, Summa Theologiae I.37.1–2.

Richard of St. Victor

Richard offers a related but distinct model. He does not reduce the Spirit to an impersonal bond between Father and Son. He understands the third person as the co-beloved who participates personally in perfectly shared love.

This helps protect the essay’s central point: the Spirit is not something created by love. The Spirit is an eternal divine person within the communion of love.

Justification

The Father, Son, and Spirit are all loving persons. The entire divine essence is love. Yet the Spirit may also be personally named Love because He proceeds eternally according to love.

The language must therefore be:

“The Holy Spirit eternally proceeds as personal Love,”

not:

“The Father and Son existed first and their love later produced another person.”

9. One Being and Three Persons

The Trinity does not claim that three beings equal one being. It claims that the one divine essence is possessed fully and indivisibly by three distinct persons.

Scripture

Gregory of Nazianzus

Gregory writes that Christians confess one God because the Godhead is one, while also confessing three persons. He says the divine nature is undivided in the distinct persons. Gregory of Nazianzus, Theological Oration 31.

Basil the Great

Basil describes the Holy Spirit as distinct from creation and eternally united with the Father and Son in the communion of the one Godhead. Basil, On the Holy Spirit.

Gregory of Nyssa

Gregory states that the Father, Son, and Holy Spirit possess one power, goodness, essence, and glory while preserving the distinction of the persons. Gregory of Nyssa, Against Eunomius, Book II.

Ambrose

Ambrose argues from Matthew 28:19 that Jesus says “name,” not “names.” He uses this to defend one divine name and nature shared by the Father, Son, and Spirit. Ambrose, On the Holy Spirit, Book I.

Justification

The Father is not the Son. The Son is not the Spirit. The Spirit is not the Father. Yet they are not three separate divine beings.

The distinction concerns who they are. The unity concerns what they are.

Three persons. One undivided divine essence.

10. What the Argument Can and Cannot Establish

This is where the wording must remain precise.

The argument strongly supports eternal personal relationship within God. It shows why the Trinity makes sense of God being eternally loving without depending upon creation. It also gives us reason to expect personal plurality rather than divine isolation.

But Scripture reveals the specific identity of the Father, Son, and Holy Spirit.

Thomas Aquinas’ Qualification

Aquinas says natural reason cannot independently discover or conclusively demonstrate the Trinity. Reason can, however, show the coherence of the revealed doctrine and demonstrate that it is not impossible.

He specifically mentions arguments from divine goodness, partnership, Word, and Love. He says they confirm the fittingness of the Trinity once the doctrine has been revealed, but should not be treated as an adequate proof by themselves. Aquinas, Summa Theologiae I.32.1.

Augustine’s Qualification

Augustine uses created examples such as mind, knowledge, and love, but warns that these remain limited images. The creature must never be treated as equal to the Creator. Augustine, On the Trinity, Book XV.

Justification

The strongest defensible form of the argument is therefore:

Reason shows that eternal relational love is fitting, expected, and more consistent with divine perfection than eternal personal isolation. Revelation then identifies that eternal communion as the Father, Son, and Holy Spirit.

This prevents the argument from becoming circular. We do not begin by assuming the Trinity and then force love to fit it. We begin with God’s perfection, actuality, freedom, and love. Those truths point toward eternal personal communion. Scripture reveals the full triune reality toward which the reasoning points.

Condensed Argument with Sources

  1. God is eternal and unchanging.
    Psalm 90:2; Malachi 3:6; James 1:17; Aquinas, ST I.9.1.

  2. God is fully actual and lacks no perfection.
    Matthew 5:48; Aquinas, ST I.4.1.

  3. God is love.
    1 John 4:8, 16; Aquinas, ST I.20.1.

  4. Other-directed, self-giving love contains a perfection isolated self-love does not.
    Matthew 22:39; John 15:13; 1 Corinthians 13:5; Richard of St. Victor, On the Trinity III.2–5.

  5. God cannot depend upon creation to acquire interpersonal love.
    Acts 17:24–25; Romans 11:35–36; Aquinas, ST I.19.3–4.

  6. The Father actually loved the Son before creation.
    John 17:5, 24.

  7. The Father and Son are eternally distinct yet possess the same divine nature.
    John 1:1–3; Basil, Letter 8; Gregory of Nazianzus, Oration 29.

  8. The Holy Spirit is an eternal divine person who proceeds personally according to love.
    John 15:26; Romans 5:5; Augustine, On the Trinity XV; Aquinas, ST I.37.

  9. The Father, Son, and Holy Spirit are three distinct persons within the one undivided Godhead.
    Matthew 28:19; 2 Corinthians 13:14; Gregory of Nazianzus, Oration 31.

  10. Therefore, the Trinity uniquely gives us an eternally complete communion of self-giving love without making God dependent upon creation.

The conclusion is not that God needed three persons in order to become love. The conclusion is that God has never needed to become anything. The Father, Son, and Holy Spirit eternally exist as the one perfect, unchanging, and loving God.