Trinitarian Unity and Diversity in One Diamond
The Christian doctrine of the Trinity asserts that God is one being who exists as three co-equal, co-eternal persons: the Father, the Son (Jesus Christ), and the Holy Spirit. This concept presents a profound unity in diversity, a single divine essence shared by three distinct persons [1, 3]. Early Christian thinkers grappled with articulating this mystery, seeking to uphold both the monotheism inherited from Judaism and the divinity of Christ and the Holy Spirit revealed in the New Testament [1].
Tertullian, an early Church Father, addressed the challenge posed by those who found the "dispensation of the Three in One" startling [1]. These believers, often the majority, understood their faith as a departure from polytheism to the worship of one true God. Tertullian clarified that while God is indeed one, this oneness must be understood in conjunction with His oikonomia, or divine economy, which distributes the unity into a Trinity [1, 3]. He emphasized that the Father, Son, and Holy Spirit are not three in "condition" but are three persons who are "All of One, by unity (that is) of substance" [3]. This means that while there are three distinct persons, they share a single divine essence, preventing any notion of polytheism [3, 8]. The unity is maintained because all three persons derive from the one God [3].
Augustine of Hippo, writing centuries later, further explored the Trinitarian nature of God, particularly in his work On the Holy Trinity. He acknowledged the difficulty in comprehending the Almighty Trinity, noting that "Rare is that soul which, 'while it speaketh of It, knows what it speaketh of'" [4]. Augustine sought to understand this divine mystery by drawing analogies from human experience, though he always stressed the limitations of such comparisons [4, 10]. He suggested that humans might consider "three things that are in themselves" as a way to exercise their minds, even while recognizing these are "far other than the Trinity" [4].
One of Augustine's key analogies involved the mind, its knowledge of itself, and its love for itself. He posited that the mind "loves itself, and itself knows itself; and these three so exist, as that the mind is neither loved nor known by any other thing at all" [5]. He concluded that these three—mind, knowledge, and love—must be "of one and the same essence" [5]. This analogy, while imperfect, aimed to illustrate how distinct aspects could share a single underlying reality. He also explored the concept of sight, noting that while one sees a single flame, the mechanism of vision involves multiple elements, though he deemed this particular inquiry "not necessary at all to our present subject" [2].
Augustine also distinguished between the simple, unchangeable nature of God and the created order. He stated that God is "a good which is alone simple, and therefore alone unchangeable," and that "By this Good have all others been created, but not simple, and therefore not unchangeable" [7]. He clarified that what is "begotten of the simple Good is simple as itself, and the same as itself," referring to the Father and the Son, and both together with the Holy Spirit [7]. This highlights the unique, uncreated nature of the Trinitarian persons in contrast to creation.
The unity of the Trinity is not a mere aggregation of parts. Augustine argued that if the three persons were "confounded together as it were by a commingling, they could not be in any way three" [5]. Instead, the unity is one of essence, while the diversity is in personhood. He explicitly rejected the idea of subdividing one essence into three substances or persons in the same way one might subdivide a group of men, because "one man is already a single man" [9]. This underscores that the divine essence is not divisible, but rather fully shared by each person of the Trinity.
The Holy Spirit, in this Trinitarian framework, is often described as the bond of love between the Father and the Son. Augustine referred to the "unspeakable conjunction of the Father and His image" (the Son) as being "not without fruition, without love, without joy" [6]. This love, delight, or blessedness is identified as the Holy Spirit, who is "not begotten, but the sweetness of the begetter and o[f the begotten]" [6]. This perspective emphasizes the relational aspect within the Godhead, where the Spirit proceeds from the Father and the Son as the very expression of their mutual love and unity.
The early Church Fathers, like Tertullian and Augustine, were careful to articulate the Trinity in a way that avoided both modalism (the idea that God is one person who appears in three different modes) and tritheism (the belief in three separate gods). Tertullian's concept of the oikonomia and Augustine's analogies, while imperfect, served to explain how God could be both one and three simultaneously [1, 3, 4]. The doctrine maintains that the Father is God, the Son is God, and the Holy Spirit is God, yet there is only one God. This is a central mystery of Christian faith, affirming both the distinct identities of the divine persons and their absolute unity in essence and purpose.
Sources
- Schaff ANF/NPNF (Patristic) “ANF Vol 3: Tertullian — CHAP. III.--SUNDRY POPULAR FEARS AND PREJUDICES. THE DOCTRINE OF THE TRINITY IN UNITY RESCUED FROM THESE MISAPPREHENSIONS. (part 1): The simple, indeed, (I will not call them unwise and unlearned,) who always constitute 599 the majority of believers, are startled at the dispensation[1] (of the Three in One), on the ground that their very rule of faith withdraws them from the world's plurality of gods to the one only true God; not understanding that, although He is the one only God, He must yet be believed in with His own <greek>oikonomia</greek>. The numerical order and”
- Schaff ANF/NPNF (Patristic) “NPNF1 Vol 3: Augustine — On the Holy Trinity — CHAP. 2.--A CERTAIN TRINITY IN THE SIGHT. THAT THERE ARE THREE THINGS IN SIGHT, WHICH DIFFER IN THEIR OWN NATURE. IN WHAT MANNER FROM A VISIBLE THING VISION IS PRODUCED, OR THE IMAGE OF THAT THING WHI (part 5): shall not see two flames, but one as it really is. But why, if we shut the left eye, that appearance ceases to be seen, which was on the right; and if, in turn, we shut the right eye, that drops out of existence which was on the left, is a matter both tedious in itself, and not necessary at all to our present subject to inquire and discuss.”
- Schaff ANF/NPNF (Patristic) “ANF Vol 3: Tertullian — CHAP. II.--THE CATHOLIC DOCTRINE OF THE TRINITY AND UNITY, SOMETIMES CALLED THE DIVINE ECONOMY, OR DISPENSATION OF THE PERSONAL RELATIONS OF THE GODHEAD. (part 2): than by saying that the Father, the Son, and the Holy Ghost are the very selfsame Person. As if in this way also one were not All, in that All are of One, by unity (that is) of substance; while the mystery of the dispensation[9] is still guarded, which distributes the Unity into a Trinity, placing in their order[10] the three Persons--the Father, the Son, and the Holy Ghost: three, however, not in condition,[”
- Schaff ANF/NPNF (Patristic) “NPNF1 Vol 1: Augustine — Confessions, Letters — CHAP. XI. --THAT THE SYMBOLS OF THE TRINITY IN MAN, TO BE, TO KNOW, AND TO WILL, ARE NEVER THOROUGHLY EXAMINED.: 12. Which of us understandeth the Almighty Trinity?10 And yet which speaketh not of It, if indeed it be It? Rare is that soul which, 'while it speaketh of It, knows what it speaketh of. And they contend and strive, but no one without peace seeth that vision. I could wish that men would consider these three things that are in themselves. These three are far other than the Trinity; but I speak of things in which' they may exercise and pr”
- Schaff ANF/NPNF (Patristic) “NPNF1 Vol 3: Augustine — On the Holy Trinity — CHAP. 4.--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 A (part 4): itself loves itself, and itself knows itself; and these three so exist, as that the mind is neither loved nor known by any other thing at all. These three, therefore, must needs be of one and the same essence; and for that reason, if they were confounded together as it were by a commingling, they could not be in any way three, neither could”
- Schaff ANF/NPNF (Patristic) “NPNF1 Vol 3: Augustine — On the Holy Trinity — CHAP. X.--OF THE ATTRIBUTES ASSIGNED BY HILARY TO EACH PERSON. THE TRINITY IS REPRESENTED IN THINGS THAT ARE MADE. (part 2): even although changeable, because they are known unchangeably by Him. Therefore that unspeakable conjunction of the Father and His image is not without fruition, without love, without joy. Therefore that love, delight, felicity, or blessedness, if indeed it can be worthily expressed by any human word, is called by him, in short, Use; and is the Holy Spirit in the Trinity, not begotten, but the sweetness of the begetter and o”
- Schaff ANF/NPNF (Patristic) “NPNF1 Vol 2: Augustine — City of God, Christian Doctrine — CHAP. 10.--OF THE SIMPLE AND UNCHANGEABLE TRINITY, FATHER, SON, AND HOLY GHOST, ONE GOD, IN WHOM SUBSTANCE AND QUALITY ARE IDENTICAL. (part 1): There is, accordingly, a good which is alone simple, and therefore alone unchangeable, and this is God. By this Good have all others been created, but not simple, and therefore not unchangeable. "Created," I say,--that is, made, not begotten. For that which is begotten of the simple Good is simple as itself, and the same as itself. These two we call the Father and the Son; and both together wit”
- Schaff ANF/NPNF (Patristic) “ANF Vol 3: Tertullian — CHAP. XIII.--THE FORCE OF SUNDRY PASSAGES OF SCRIPTURE ILLUSTRATED IN RELATION TO THE PLURALITY OF PERSONS AND UNITY OF SUBSTANCE. THERE IS NO POLYTHEISM HERE, SINCE THE UNITY IS INSISTED (part 3): Christ would justly enough be inadmissible to the title of God and Lord: for (in the Scriptures) there was declared to be none other than One God and One Lord, and it must have followed that the Father should Himself seem to have come down (to earth), inasmuch as only One God and One Lord was ever read of (in the Scriptures), and His entire Economy would be invol”
- Schaff ANF/NPNF (Patristic) “NPNF1 Vol 3: Augustine — On the Holy Trinity — CHAP. 6.--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, AN (part 3): Abraham, Isaac, and Jacob, so can one man also be subdivided rate several single men; for this is altogether impossible, since one man is already a single man. Why then is one essence subdivided into three substances or persons? For if essence is a species, as man is, then one essence is as one man is: or do we, as we say that any three hum”
- Schaff ANF/NPNF (Patristic) “NPNF1 Vol 3: Augustine — On the Holy Trinity — CHAP. 23.--AUGUSTIN DWELLS STILL FURTHER ON THE DISPARITY BETWEEN THE TRINITY WHICH IS IN MAN, AND THE TRINITY WHICH IS GOD. THE TRINITY IS NOW SEEN THROUGH A GLASS BY THE HELP OF FAITH, THAT IT MAY H (part 1): 43. A thing itself, then, which is a trinity is different from the image of a trinity in some other thing; by reason of which image, at the same time that also in which these three things are is called an image; just as both the panel, and the picture painted on it, are at the same time called an image; but by reason of the picture painted ”