On the Trinity
Augustine of Hippo (354–430)
First published 428
Augustine's De Trinitate, staged here in the public-domain NPNF English translation by Arthur West Haddan, revised by W. G. T. Shedd.
Book 1
Caput I: This Work is Written Against Those Who Sophistically Assail the Faith of the Trinity, Through Misuse of Reason. They Who Dispute Concerning God Err from a Threefold Cause. Holy Scripture, Removing What is False, Leads Us on by Degrees to Things Divine. What True Immortality is. We are Nourished by Faith, that We May Be Enabled to Apprehend Things Divine.
Caput II: In What Manner This Work Proposes to Discourse Concerning the Trinity.
Caput III: What Augustin Requests from His Readers. The Errors of Readers Dull of Comprehension Not to Be Ascribed to the Author.
Caput IV: What the Doctrine of the Catholic Faith is Concerning the Trinity.
Caput V: Of Difficulties Concerning the Trinity: in What Manner Three are One God, and How, Working Indivisibly, They Yet Perform Some Things Severally.
Caput VI: That the Son is Very God, of the Same Substance with the Father. Not Only the Father, But the Trinity, is Affirmed to Be Immortal. All Things are Not from the Father Alone, But Also from the Son. That the Holy Spirit is Very God, Equal with the Father and the Son.
Caput VII: In What Manner the Son is Less Than the Father, and Than Himself.
Caput VIII: The Texts of Scripture Explained Respecting the Subjection of the Son to the Father, Which Have Been Misunderstood. Christ Will Not So Give Up the Kingdom to the Father, as to Take It Away from Himself. The Beholding Him is the Promised End of All Actions. The Holy Spirit is Sufficient to Our Blessedness Equally with the Father.
Caput IX: All are Sometimes Understood in One Person.
Caput X: In What Manner Christ Shall Deliver Up the Kingdom to God, Even the Father. The Kingdom Having Been Delivered to God, Even the Father, Christ Will Not Then Make Intercession for Us.
Caput XI: By What Rule in the Scriptures It is Understood that the Son is Now Equal and Now Less.
Caput XII: In What Manner the Son is Said Not to Know the Day and the Hour Which the Father Knows. Some Things Said of Christ According to the Form of God, Other Things According to the Form of a Servant. In What Way It is of Christ to Give the Kingdom, in What Not of Christ. Christ Will Both Judge and Not Judge.
Caput XIII: Diverse Things are Spoken Concerning the Same Christ, on Account of the Diverse Natures of the One Hypostasis [Theanthropic Person]. Why It is Said that the Father Will Not Judge, But Has Given Judgment to the Son.
Book 2
Caput I: Preface
Caput I: There is a Double Rule for Understanding the Scriptural Modes of Speech Concerning the Son of God. These Modes of Speech are of a Threefold Kind.
Caput II: That Some Ways of Speaking Concerning the Son are to Be Understood According to Either Rule.
Caput III: Some Things Concerning the Holy Spirit are to Be Understood According to the One Rule Only.
Caput IV: The Glorification of the Son by the Father Does Not Prove Inequality.
Caput V: The Son and Holy Spirit are Not Therefore Less Because Sent. The Son is Sent Also by Himself. Of the Sending of the Holy Spirit.
Caput VI: The Creature is Not So Taken by the Holy Spirit as Flesh is by the Word.
Caput VII: A Doubt Raised About Divine Appearances.
Caput VIII: The Entire Trinity Invisible.
Caput IX: Against Those Who Believed the Father Only to Be Immortal and Invisible. The Truth to Be Sought by Peaceful Study.
Caput X: Whether God the Trinity Indiscriminately Appeared to the Fathers, or Any One Person of the Trinity. The Appearing of God to Adam. Of the Same Appearance. The Vision to Abraham.
Caput XI: Of the Same Appearance.
Caput XII: The Appearance to Lot is Examined.
Caput XIII: The Appearance in the Bush.
Caput XIV: Of the Appearance in the Pillar of Cloud and of Fire.
Caput XV: Of the Appearance on Sinai. Whether the Trinity Spake in that Appearance or Some One Person Specially.
Caput XVI: In What Manner Moses Saw God.
Caput XVII: How the Back Parts of God Were Seen. The Faith of the Resurrection of Christ. The Catholic Church Only is the Place from Whence the Back Parts of God are Seen. The Back Parts of God Were Seen by the Israelites. It is a Rash Opinion to Think that God the Father Only Was Never Seen by the Fathers.
Caput XVIII: The Vision of Daniel.
Book 3
Caput I: Preface
Caput I: What is to Be Said Thereupon.
Caput II: The Will of God is the Higher Cause of All Corporeal Change. This is Shown by an Example.
Caput III: Of the Same Argument.
Caput IV: God Uses All Creatures as He Will, and Makes Visible Things for the Manifestation of Himself.
Caput V: Why Miracles are Not Usual Works.
Caput VI: Diversity Alone Makes a Miracle.
Caput VII: Great Miracles Wrought by Magic Arts.
Caput VIII: God Alone Creates Those Things Which are Changed by Magic Art.
Caput IX: The Original Cause of All Things is from God.
Caput X: In How Many Ways the Creature is to Be Taken by Way of Sign. The Eucharist.
Caput XI: The Essence of God Never Appeared in Itself. Divine Appearances to the Fathers Wrought by the Ministry of Angels. An Objection Drawn from the Mode of Speech Removed. That the Appearing of God to Abraham Himself, Just as that to Moses, Was Wrought by Angels. The Same Thing is Proved by the Law Being Given to Moses by Angels. What Has Been Said in This Book, and What Remains to Be Said in the Next.
Book 4
Caput I: Preface
Caput I: We are Made Perfect by Acknowledgement of Our Own Weakness. The Incarnate Word Dispels Our Darkness.
Caput II: How We are Rendered Apt for the Perception of Truth Through the Incarnate Word.
Caput III: The One Death and Resurrection of The Body of Christ Harmonizes with Our Double Death and Resurrection of Body and Soul, to the Effect of Salvation. In What Way the Single Death of Christ is Bestowed Upon Our Double Death.
Caput IV: The Ratio of the Single to the Double Comes from the Perfection of the Senary Number. The Perfection of The Senary Number is Commended in the Scriptures. The Year Abounds in The Senary Number.
Caput V: The Number Six is Also Commended in the Building Up of the Body of Christ and of the Temple at Jerusalem.
Caput VI: The Three Days of the Resurrection, in Which Also the Ratio of Single to Double is Apparent.
Caput VII: In What Manner We are Gathered from Many into One Through One Mediator.
Caput VIII: In What Manner Christ Wills that All Shall Be One in Himself.
Caput IX: The Same Argument Continued.
Caput X: As Christ is the Mediator of Life, So the Devil is the Mediator of Death.
Caput XI: Miracles Which are Done by Demons are to Be Spurned.
Caput XII: The Devil the Mediator of Death, Christ of Life.
Caput XIII: The Death of Christ Voluntary. How the Mediator of Life Subdued the Mediator of Death. How the Devil Leads His Own to Despise the Death of Christ.
Caput XIV: Christ the Most Perfect Victim for Cleansing Our Faults. In Every Sacrifice Four Things are to Be Considered.
Caput XV: They are Proud Who Think They are Able, by Their Own Righteousness, to Be Cleansed So as to See God.
Caput XVI: The Old Philosophers are Not to Be Consulted Concerning the Resurrection and Concerning Things to Come.
Caput XVII: In How Many Ways Things Future are Foreknown. Neither Philosophers, Nor Those Who Were Distinguished Among the Ancients, are to Be Consulted Concerning the Resurrection of the Dead.
Caput XVIII: The Son of God Became Incarnate in Order that We Being Cleansed by Faith May Be Raised to the Unchangeable Truth.
Caput XIX: In What Manner the Son Was Sent and Proclaimed Beforehand. How in the Sending of His Birth in the Flesh He Was Made Less Without Detriment to His Equality with the Father.
Caput XX: The Sender and the Sent Equal. Why the Son is Said to Be Sent by the Father. Of the Mission of the Holy Spirit. How and by Whom He Was Sent. The Father the Beginning of the Whole Godhead.
Caput XXI: Of the Sensible Showing of the Holy Spirit, and of the Coeternity of the Trinity. What Has Been Said, and What Remains to Be Said.
Book 5
Caput I: What the Author Entreats from God, What from the Reader. In God Nothing is to Be Thought Corporeal or Changeable.
Caput II: God the Only Unchangeable Essence.
Caput III: The Argument of the Arians is Refuted, Which is Drawn from the Words Begotten and Unbegotten.
Caput IV: The Accidental Always Implies Some Change in the Thing.
Caput V: Nothing is Spoken of God According to Accident, But According to Substance or According to Relation.
Caput VI: Reply is Made to the Cavils of the Heretics in Respect to the Same Words Begotten and Unbegotten.
Caput VII: The Addition of a Negative Does Not Change the Predicament.
Caput VIII: Whatever is Spoken of God According to Substance, is Spoken of Each Person Severally, and Together of the Trinity Itself. One Essence in God, and Three, in Greek, Hypostases, in Latin, Persons.
Caput IX: The Three Persons Not Properly So Called [in a Human Sense].
Caput X: Those Things Which Belong Absolutely to God as an Essence, are Spoken of the Trinity in the Singular, Not in the Plural.
Caput XI: What is Said Relatively in the Trinity.
Caput XII: In Relative Things that are Reciprocal, Names are Sometimes Wanting.
Caput XIII: How the Word Beginning (Principium) is Spoken Relatively in the Trinity.
Caput XIV: The Father and the Son the Only Beginning (Principium) of the Holy Spirit.
Caput XV: Whether the Holy Spirit Was a Gift Before as Well as After He Was Given.
Caput XVI: What is Said of God in Time, is Said Relatively, Not Accidentally.
Book 6
Caput I: The Son, According to the Apostle, is the Power and Wisdom of the Father. Hence the Reasoning of the Catholics Against the Earlier Arians. A Difficulty is Raised, Whether the Father is Not Wisdom Himself, But Only the Father of Wisdom.
Caput II: What is Said of the Father and Son Together, and What Not.
Caput III: That the Unity of the Essence of the Father and the Son is to Be Gathered from the Words, ‘We are One.’ The Son is Equal to the Father Both in Wisdom and in All Other Things.
Caput IV: The Same Argument Continued.
- For in like manner the virtues which are in the human mind, although each has its own several and different meaning, yet are in no way mutually separable; so that, for instance, whosoever were equal in courage, are equal also in prudence, and temperance, and justice. For if you say that such and such men are equal in courage, but that one of them is greater in prudence, it follows that the courage of the other is less prudent, and so neither are they equal in courage, since the courage of the former is more prudent. And so you will find it to be the case with the other virtues, if you consider them one by one. For the question is not of the strength of the body, but of the courage of the mind. How much more therefore is this the case in that unchangeable and eternal substance, which is incomparably more simple than the human mind is? Since, in the human mind, to be is not the same as to be strong, or prudent, or just, or temperate; for a mind can exist, and yet have none of these virtues. But in God to be is the same as to be strong, or to be just, or to be wise, or whatever is said of that simple multiplicity, or multifold simplicity, whereby to signify His substance. Wherefore, whether we say God of God in such way that this name belongs to each, yet not so that both together are two Gods, but one God; for they are in such way united with each other, as according to the apostle’s testimony may take place even in diverse and differing substances; for both the Lord alone is a Spirit, and the spirit of a man alone is assuredly a spirit; yet, if it cleave to the Lord, “it is one spirit:” how much more there, where there is an absolutely inseparable and eternal union, so that He may not seem absurdly to be called as it were the Son of both, when He is called the Son of God, if that which is called God is only said of both together. Or perhaps it is, that whatever is said of God so as to indicate His substance, is not said except of both together, nay of the Trinity itself together? Whether therefore it be this or that (which needs a closer inquiry), it is enough for the present to see from what has been said, that the Son is in no respect equal with the Father, if He is found to be unequal in anything which has to do with signifying His substance, as we have already shown. But the apostle has said that He is equal. Therefore the Son is equal with the Father in all things, and is of one and the same substance.