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.
- But when Moses was sent to lead the children of Israel out of Egypt, it is written that the Lord appeared to him thus: “Now Moses kept the flock of Jethro his father-in-law, the priest of Midian: and he led the flock to the back side of the desert, and came to the mountain of God, even to Horeb. And the Angel of the Lord appeared unto him in a flame of fire, out of the midst of a bush; and he looked, and, behold, the bush burned with fire, and the bush was not consumed. And Moses said, I will now turn aside, and see this great sight, why the bush is not burnt. And when the Lord saw that he turned aside to see, God called unto him out of the midst of the bush, and said, I am the God of thy father, the God of Abraham, the God of Isaac, and the God of Jacob.” He is here also first called the Angel of the Lord, and then God. Was an angel, then, the God of Abraham, and the God of Isaac, and the God of Jacob? Therefore He may be rightly understood to be the Saviour Himself, of whom the apostle says, “Whose are the fathers, and of whom as concerning the flesh Christ came, who is over all, God blessed for ever.” He, therefore, “who is over all, God blessed for ever,” is not unreasonably here understood also to be Himself the God of Abraham, the God of Isaac, and the God of Jacob. But why is He previously called the Angel of the Lord, when He appeared in a flame of fire out of the bush? Was it because it was one of many angels, who by an economy [or arrangement] bare the person of his Lord? or was something of the creature assumed by Him in order to bring about a visible appearance for the business in hand, and that words might thence be audibly uttered, whereby the presence of the Lord might be shown, in such way as was fitting, to the corporeal senses of man, by means of the creature made subject? For if he was one of the angels, who could easily affirm whether it was the person of the Son which was imposed upon him to announce, or that of the Holy Spirit, or that of God the Father, or altogether of the Trinity itself, who is the one and only God, in order that he might say, “I am the God of Abraham, and the God of Isaac, and the God of Jacob?” For we cannot say that the Son of God is the God of Abraham, and the God of Isaac, and the God of Jacob, and that the Father is not; nor will any one dare to deny that either the Holy Spirit, or the Trinity itself, whom we believe and understand to be the one God, is the God of Abraham, and the God of Isaac, and the God of Jacob. For he who is not God, is not the God of those fathers. Furthermore, if not only the Father is God, as all, even heretics, admit; but also the Son, which, whether they will or not, they are compelled to acknowledge, since the apostle says, “Who is over all, God blessed for ever;” and the Holy Spirit, since the same apostle says, “Therefore glorify God in your body;” when he had said above, “Know ye not that your body is the temple of the Holy Ghost, which is in you, which ye have of God?” and these three are one God, as catholic soundness believes: it is not sufficiently apparent which person of the Trinity that angel bare, if he was one of the rest of the angels, and whether any person, and not rather that of the Trinity itself. But if the creature was assumed for the purpose of the business in hand, whereby both to appear to human eyes, and to sound in human ears, and to be called the Angel of the Lord, and the Lord, and God; then cannot God here be understood to be the Father, but either the Son or the Holy Spirit. Although I cannot call to mind that the Holy Spirit is anywhere else called an angel, which yet may be understood from His work; for it is said of Him, “And He will show you things to come;” and “angel” in Greek is certainly equivalent to “messenger” in Latin: but we read most evidently of the Lord Jesus Christ in the prophet, that He is called “the Angel of Great Counsel,” while both the Holy Spirit and the Son of God is God and Lord of the angels.