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.
Caput V: The Holy Spirit Also is Equal to the Father and the Son in All Things.
Caput VI: How God is a Substance Both Simple and Manifold.
Caput VII: God is a Trinity, But Not Triple (Triplex).
Caput VIII: No Addition Can Be Made to the Nature of God.
Caput IX: Whether One or the Three Persons Together are Called the Only God.
Caput X: Of the Attributes Assigned by Hilary to Each Person. The Trinity is Represented in Things that are Made.
Book 7
Caput I: Augustin Returns to the Question, Whether Each Person of the Trinity by Itself is Wisdom. With What Difficulty, or in What Way, the Proposed Question is to Be Solved.
Caput II: The Father and the Son are Together One Wisdom, as One Essence, Although Not Together One Word.
Caput III: Why the Son Chiefly is Intimated in the Scriptures by the Name of Wisdom, While Both the Father and the Holy Spirit are Wisdom. That the Holy Spirit, Together with the Father and the Son, is One Wisdom.
Caput IV: How It Was Brought About that the Greeks Speak of Three Hypostases, the Latins of Three Persons. Scripture Nowhere Speaks of Three Persons in One God.
Caput V: In God, Substance is Spoken Improperly, Essence Properly.
Caput VI: Why We Do Not in the Trinity Speak of One Person, and Three Essences. What He Ought to Believe Concerning the Trinity Who Does Not Receive What is Said Above. Man is Both After the Image, and is the Image of God.
Book 8
Caput I: Preface.—The Conclusion of What Has Been Said Above. The Rule to Be Observed in the More Difficult Questions of the Faith.
Caput I: It is Shown by Reason that in God Three are Not Anything Greater Than One Person.
Caput II: Every Corporeal Conception Must Be Rejected, in Order that It May Be Understood How God is Truth.
Caput III: How God May Be Known to Be the Chief Good. The Mind Does Not Become Good Unless by Turning to God.
Caput IV: God Must First Be Known by an Unerring Faith, that He May Be Loved.
Caput V: How the Trinity May Be Loved Though Unknown.
Caput VI: How the Man Not Yet Righteous Can Know the Righteous Man Whom He Loves.
Caput VII: Of True Love, by Which We Arrive at the Knowledge of the Trinity. God is to Be Sought, Not Outwardly, by Seeking to Do Wonderful Things with the Angels, But Inwardly, by Imitating the Piety of Good Angels.
Caput VIII: That He Who Loves His Brother, Loves God; Because He Loves Love Itself, Which is of God, and is God.
Caput IX: Our Love of the Righteous is Kindled from Love Itself of the Unchangeable Form of Righteousness.
Caput X: There are Three Things in Love, as It Were a Trace of the Trinity.
Book 9
Caput I: In What Way We Must Inquire Concerning the Trinity.
Caput II: The Three Things Which are Found in Love Must Be Considered.
Caput III: The Image of the Trinity in the Mind of Man Who Knows Himself and Loves Himself. The Mind Knows Itself Through Itself.
Caput IV: The Three are One, and Also Equal, Viz. The Mind Itself, and the Love, and the Knowledge of It. That the Same Three Exist Substantially, and are Predicated Relatively. That the Same Three are Inseparable. That the Same Three are Not Joined and Commingled Like Parts, But that They are of One Essence, and are Relatives.
Caput V: That These Three are Several in Themselves, and Mutually All in All.
Caput VI: There is One Knowledge of the Thing in the Thing Itself, and Another in Eternal Truth Itself. That Corporeal Things, Too, are to Be Judged the Rules of Eternal Truth.
Caput VII: We Conceive and Beget the Word Within, from the Things We Have Beheld in the Eternal Truth. The Word, Whether of the Creature or of the Creator, is Conceived by Love.
Caput VIII: In What Desire and Love Differ.
Caput IX: In the Love of Spiritual Things the Word Born is the Same as the Word Conceived. It is Otherwise in the Love of Carnal Things.
Caput X: Whether Only Knowledge that is Loved is the Word of the Mind.
Caput XI: That the Image or Begotten Word of the Mind that Knows Itself is Equal to the Mind Itself.
Caput XII: Why Love is Not the Offspring of the Mind, as Knowledge is So. The Solution of the Question. The Mind with the Knowledge of Itself and the Love of Itself is the Image of the Trinity.
Book 10
Caput I: The Love of the Studious Mind, that Is, of One Desirous to Know, is Not the Love of a Thing Which It Does Not Know.
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Let us now proceed, then, in due order, with a more exact purpose, to explain this same point more thoroughly. And first, since no one can love at all a thing of which he is wholly ignorant, we must carefully consider of what sort is the love of those who are studious, that is, of those who do not already know, but are still desiring to know any branch of learning. Now certainly, in those things whereof the word study is not commonly used, love often arises from hearsay, when the reputation of anything for beauty inflames the mind to the seeing and enjoying it; since the mind knows generically wherein consist the beauties of corporeal things, from having seen them very frequently, and since there exists within a faculty of approving that which outwardly is longed for. And when this happens, the love that is called forth is not of a thing wholly unknown, since its genus is thus known. But when we love a good man whose face we never saw, we love him from the knowledge of his virtues, which virtues we know [abstractly] in the truth itself. But in the case of learning, it is for the most part the authority of others who praise and commend it that kindles our love of it; although nevertheless we could not burn with any zeal at all for the study of it, unless we had already in our mind at least a slight impression of the knowledge of each kind of learning. For who, for instance, would devote any care and labor to the learning of rhetoric, unless he knew before that it was the science of speaking? Sometimes, again, we marvel at the results of learning itself, which we have heard of or experienced; and hence burn to obtain, by learning, the power of attaining these results. Just as if it were said to one who did not know his letters, that there is a kind of learning which enables a man to send words, wrought with the hand in silence, to one who is ever so far absent, for him in turn to whom they are sent to gather these words, not with his ears, but with his eyes; and if the man were to see the thing actually done, is not that man, since he desires to know how he can do this thing, altogether moved to study with a view to the result which he already knows and holds? So it is that the studious zeal of those who learn is kindled: for that of which any one is utterly ignorant, he can in no way love.
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So also, if any one hear an unknown sign, as, for instance, the sound of some word of which he does not know the signification, he desires to know what it is; that is, he desires to know what thing it is which it is agreed shall be brought to mind by that sound: as if he heard the word temetum uttered, and not knowing, should ask what it is. He must then know already that it is a sign, i.e. that the word is not an empty sound, but that something is signified by it; for in other respects this trisyllabic word is known to him already, and has already impressed its articulate form upon his mind through the sense of hearing. And then what more is to be required in him, that he may go on to a greater knowledge of that of which all the letters and all the spaces of its several sounds are already known, unless that it shall at the same time have become known to him that it is a sign, and shall have also moved him with the desire of knowing of what it is the sign? The more, then, the thing is known, yet not fully known, the more the mind desires to know concerning it what remains to be known. For if he knew it to be only such and such a spoken word, and did not know that it was the sign of something, he would seek nothing further, since the sensible thing is already perceived as far as it can be by the sense. But because he knows it to be not only a spoken word, but also a sign, he wishes to know it perfectly; and no sign is known perfectly, except it be known of what it is the sign. He then who with ardent carefulness seeks to know this, and inflamed by studious zeal perseveres in the search; can such an one be said to be without love? What then does he love? For certainly nothing can be loved unless it is known. For that man does not love those three syllables which he knows already. But if he loves this in them, that he knows them to signify something, this is not the point now in question, for it is not this which he seeks to know. But we are now asking what it is he loves, in that which he is desirous to know, but which certainly he does not yet know; and we are therefore wondering why he loves, since we know most assuredly that nothing can be loved unless it be known. What then does he love, except that he knows and perceives in the reason of things what excellence there is in learning, in which the knowledge of all signs is contained; and what benefit there is in the being skilled in these, since by them human fellowship mutually communicates its own perceptions, lest the assemblies of men should be actually worse than utter solitude, if they were not to mingle their thoughts by conversing together? The soul, then, discerns this fitting and serviceable species, and knows it, and loves it; and he who seeks the meaning of any words of which he is ignorant, studies to render that species perfect in himself as much as he can: for it is one thing to behold it in the light of truth, another to desire it as within his own capacity. For he beholds in the light of truth how great and how good a thing it is to understand and to speak all tongues of all nations, and so to hear no tongue and to be heard by none as from a foreigner. The beauty, then, of this knowledge is already discerned by thought, and the thing being known is loved; and that thing is so regarded, and so stimulates the studious zeal of learners, that they are moved with respect to it, and desire it eagerly in all the labor which they spend upon the attainment of such a capacity, in order that they may also embrace in practice that which they know beforehand by reason. And so every one, the nearer he approaches that capacity in hope, the more fervently desires it with love; for those branches of learning are studied the more eagerly, which men do not despair of being able to attain; for when any one entertains no hope of attaining his end, then he either loves lukewarmly or does not love at all, howsoever he may see the excellence of it. Accordingly, because the knowledge of all languages is almost universally felt to be hopeless, every one studies most to know that of his own nation; but if he feels that he is not sufficient even to comprehend this perfectly, yet no one is so indolent in this knowledge as not to wish to know, when he hears an unknown word, what it is, and to seek and learn it if he can. And while he is seeking it, certainly he has a studious zeal of learning, and seems to love a thing he does not know; but the case is really otherwise. For that species touches the mind, which the mind knows and thinks, wherein the fitness is clearly visible which accrues from the associating of minds with one another, in the hearing and returning of known and spoken words. And this species kindles studious zeal in him who seeks what indeed he knows not, but gazes upon and loves the unknown form to which that pertains. If then, for example, any one were to ask, What is temetum (for I had instanced this word already), and it were said to him, What does this matter to you? he will answer, Lest perhaps I hear some one speaking, and understand him not; or perhaps read the word somewhere, and know not what the writer meant. Who, pray, would say to such an inquirer, Do not care about understanding what you hear; do not care about knowing what you read? For almost every rational soul quickly discerns the beauty of that knowledge, through which the thoughts of men are mutually made known by the enunciation of significant words; and it is on account of this fitness thus known, and because known therefore loved, that such an unknown word is studiously sought out. When then he hears and learns that wine was called “temetum” by our forefathers, but that the word is already quite obsolete in our present usage of language, he will think perhaps that he has still need of the word on account of this or that book of those forefathers. But if he holds these also to be superfluous, perhaps he does now come to think the word not worth remembering, since he sees it has nothing to do with that species of learning which he knows with the mind, and gazes upon, and so loves.
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Wherefore in all cases the love of a studious mind, that is, of one that wishes to know what it does not know, is not the love of that thing which it does not know, but of that which it knows; on account of which it wishes to know what it does not know. Or if it is so inquisitive as to be carried away, not for any other cause known to it, but by the mere love of knowing things unknown; then such an inquisitive person is, doubtless distinguishable from an ordinary student, yet does not, any more than he, love things he does not know; nay, on the contrary, he is more fitly said to hate things he knows not, of which he wishes that there should be none, in wishing to know everything. But lest any one should lay before us a more difficult question, by declaring that it is just as impossible for any one to hate what he does not know, as to love what he does not know, we will not withstand what is true; but it must be understood that it is not the same thing to say he loves to know things unknown, as to say he loves things unknown. For it is possible that a man may love to know things unknown; but it is not possible that he should love things unknown. For the word to know is not placed there without meaning; since he who loves to know things unknown, does not love the unknown things themselves, but the knowing of them. And unless he knew what knowing means, no one could say confidently, either that he knew or that he did not know. For not only he who says I know, and says so truly, must needs know what knowing is; but he also who says, I do not know, and says so confidently and truly, and knows that he says so truly, certainly knows what knowing is; for he both distinguishes him who does not know from him who knows, when he looks into himself and says truly I do not know; and whereas he knows that he says this truly, whence should he know it, if he did not know what knowing is?