God the Father
Definition of Terms:
In Catholic theology, God the Father is understood as the first person of the Holy Trinity, which is the central doctrine of Christian belief. God the Father is considered the creator and sustainer of the universe, the source of all existence and life. As the Father, he is seen as having a personal relationship with humanity, caring for and guiding his creation with love and mercy. Below, we will discuss;
Proofs of Existence:
For centuries, philosophers have pondered the existence of reality and the essence of God. Both philosophy and theology have offered distinct yet complementary approaches to understanding the existence and attributes of God. Philosophy, through reason and logical analysis, seeks to establish the existence of God based on rational arguments and the examination of evidence from the natural world. Theology, on the other hand, draws on the insights and truths revealed through both logic and Divine Revelation to explore the nature and attributes of God.
Plato (427-347 BCE), the ancient Greek philosopher, contributed significantly to various areas of philosophy, including metaphysics, ethics, politics, and epistemology. Plato posited the existence of an abstract realm of Forms or Ideas. According to him, the physical world we perceive is a mere reflection or imperfect copy of these ideal Forms. The Forms represent perfect and unchanging essences that serve as the ultimate reality. He considered the soul as distinct from the body, asserting its immortality and its capacity to access knowledge of the Forms. The graduated perfections of being actually existing in the universe can be undertood only by comparison with an absolute standard, i.e. an infinitely perfect Being. In addition, a completely materialistic view of the universe cannot account for abstract truths such as mathematics and physics; neither can it account for the human mind, consciousness, intelligence, and abstract thought.
Aristotle (384-322 BCE), a student of Plato’s gave an argument for God often referred to as the “First Cause” or “Unmoved Mover” argument. According to Aristotle, everything in the world has a cause and is subject to change. However, this chain of causality cannot regress infinitely; there must be a primary cause or source of motion that sets everything in motion without itself being moved or caused. Aristotle identified this primary cause as the “Unmoved Mover” or God. The Unmoved Mover is a necessary being that exists outside of the chain of causality, eternal and unchanging. It is the ultimate source of all motion and causation in the universe.
Augustine of Hippo (354-430 A.D.), a 4th and 5th century philosopher and theologian, put forward several arguments for the existence of God. Augustine believed that the beauty, order, and harmony present in the world are indicative of a divine creator. He also emphasized the human experience of longing for a higher, transcendent reality and ultimate fulfillment as pointing to the existence of God. Augustine also proposed the Argument from Moral Consciousness: Augustine contended that our sense of morality and conscience points to the existence of God as the ultimate standard of goodness. He believed that our innate understanding of right and wrong reflects God’s moral nature. In addition, according to his view, God is the ultimate source of all knowledge, and our ability to comprehend truth stems from His divine assistance.
Anselm of Canterbury (1033-1109 A.D.), an 11th-century philosopher and theologian, is best known for his ontological argument presented in his work “Proslogion.” Anselm defines God as “that than which nothing greater can be conceived.” Anselm argues that the concept of God necessarily includes existence because it is greater for a being to exist in reality than to exist solely as an idea. This means that if a being exists, it possesses a greater degree of reality or perfection than a being that does not exist. Based on this reasoning, Anselm concludes that God must necessarily exist. If God did not exist, then God would not be the greatest conceivable being, which would be a contradiction. Despite critiques, Anselm’s ontological argument remains a significant and influential contribution to the philosophy of religion and the discussion of God’s existence.
Thomas Aquinas (1225-1274), a 13th century philosopher and theologian, is renowned for his extensive work in merging Christian theology with Aristotelian philosophy. His crowning work, the Summa Theologica, is considered one of the most significant contributions to philosophy and a cornerstone to scholasticism. One makes this work even more noteworthy is that Aquinas intended it to be an “introduction for novices” to philosophy. In it, Aquinas presented several arguments for the existence of God, with the most famous being his Five Ways:
- The Argument from Motion: Aquinas observed that things in the world are in a state of motion or change. For anything to move or change, it must be set in motion by something else. However, this chain of movers cannot regress infinitely, so there must be an Unmoved Mover who is the source of all motion. Aquinas identifies this Unmoved Mover as God.
- The Argument from Efficient Cause: According to Aquinas, everything in the world has a cause. Nothing can be its own cause, and an infinite regress of causes is not possible. Therefore, there must be a First Cause, which is uncaused and initiated everything into existence. Aquinas identifies this First Cause as God.
- The Argument from Contingency: Aquinas argued that everything we observe in the world is contingent, meaning it depends on something else for its existence. If everything were contingent, there would be a time when nothing existed. However, since things do exist now, there must be a necessary being (non-contingent) that brings all contingent beings into existence. Aquinas identifies this necessary being as God.
- The Argument from Degree: Aquinas noticed that things in the world possess varying degrees of qualities like goodness, truth, and beauty. For such gradations to exist, there must be a standard of perfection against which they are measured. Aquinas argues that this ultimate standard is God, the being of pure perfection.
- The Argument from Final Cause (Teleological Argument): Aquinas observed that natural things tend to behave in a purposeful manner, as if directed towards specific ends. This teleological order in the universe suggests the existence of an intelligent designer who set things in motion and imbued them with purpose.It was once commonly believed that the evolutionary hypothesis disproved the teleological argument. However, it is now acknowledged that the opposite is true. The evidence of design found in the universe becomes even more impressive when viewed from an evolutionary standpoint. To suggest that something as biologically complex as the human organism came about not only by blind chance, but by a series of blind chances taking place over the course of millions of years while at the same time denying some directing intelligence is patently absurd. “Natural selection” and “survival of the fittest” merely describe the process of evolution without helping in the least to explain it; they ultimately rely on nothing more than blind chance.
René Descartes (1596-1650 A.D.), a 17th-century French philosopher, mathematician, and scientist, put forth several arguments for the existence of God, which have had a profound influence on the history of philosophy and continue to be studied and debated by scholars today. Descartes’ causal argument is based on the idea that there must be an ultimate cause for the existence of everything in the world. The chain of cause and effect cannot extend infinitely backward; there must be a first cause that sets everything into motion. This first cause, according to Descartes, is God.
While both Descartes and Aquinas discussed the idea of a “first mover,” their concepts differed significantly;
Descartes’ First Mover:
Descartes’ idea of a “first mover” sought to establish the existence of God as the necessary cause behind the existence of the universe. In Descartes’ view, God is the initial cause that set the universe into motion, and this causal principle explains the existence and operation of everything in the world.
Aquinas’ First Mover (Prime Mover); drawing on Aristotelian philosophy, proposed the concept of the “Prime Mover” as the ultimate cause of motion and change in the world. It refers to a being that imparts motion to all other moving things in an unbroken chain of causation. The Prime Mover itself is unmoved and exists outside the realm of change, being the source of all motion and existence.
So, while Descartes’ first mover relates to the origin of the universe as the initial cause, Aquinas’ Prime Mover is an ongoing, timeless, and unchanging source of motion and causation that sustains the universe in its continuous activity.
Gottfried Wilhelm Leibniz (1646-1716), a German philosopher and mathematician, presented several arguments for the existence of God. One of his most well-known arguments is the Principle of Sufficient Reason, which states that everything that exists has a reason or explanation for its existence. This principle leads to the necessity of a sufficient reason for the existence of the universe. Leibniz then formulated the argument from contingency, which proposes that contingent beings (those whose existence is dependent on other factors) cannot explain their own existence and therefore require a purely necessary being (God) as the ultimate explanation for all contingent things.
William Paley (1743-1805), an 18th-century English theologian and philosopher presented the “watchmaker” analogy argument in his book “Natural Theology; or, Evidences of the Existence and Attributes of the Deity,” published in 1802. While the “watchmaker” argument (teleological argument) has been popular and widely discussed, it has also faced criticism from various perspectives. The argument relies on an analogy between the complexity and order in a watch (man-made object) and the complexity and order in nature (natural world). Critics argue that an analogy between human-made objects and the universe is not sufficient to draw conclusions about the existence and nature of a divine creator. The “watchmaker” argument assumes that because we cannot explain the complexity of nature through natural processes, it must be the result of an intelligent designer. This reasoning is often criticized as an argument from ignorance, where the lack of a natural explanation is used to infer the existence of God. However, just because we don’t have a complete understanding of natural processes doesn’t necessarily mean that a supernatural explanation is the only option. Some proponents of evolution and natural processes contend that the complexity observed in the natural world can arise from simpler, natural processes over long periods of time. As scientific knowledge advances, natural explanations for various phenomena continue to emerge. The argument’s reliance on gaps in scientific understanding weakens as we uncover more about the natural processes that contribute to the complexity of the universe.
In Christian theology, God is described as having several attributes that help us understand His nature and character:
- Simplicity: This is God’s most fundamental and necessary attribute. God, as the most fundamental aspect of reality, serves as the foundation for all existence and is devoid of composition. If God is necessary and independent, He cannot depend on anything else for His existence, including any unity of parts. As pure act and the source of all change, God cannot possess potential within parts that can be actualized. God is the very act of being itself.
- Unity: From God’s simplicity, it logically follows that there is only one God. The perfection of creatures is diverse and numerous and differ in kind and degree, while God’s perfection is complete, uniform, and simple. If God’s defining quality is being undivided and unlimited, multiple Gods would limit each other, negating their claims to infinity. Each would lack something the other possesses, distinguishing them as separate beings.
- Trinity: God exists as a triune being, comprising Father, Son (Jesus Christ), and Holy Spirit—three distinct persons in one God. The understanding of the Trinity is only attainable through Divine Revelation, surpassing human comprehension. Although the Trinity affirms that God exists as three persons, it does not contradict their unity, because they are not divided in their being or essence, but only in their relation, each possessing the infinite divine nature and acting in perfect unity.
- Good & Just: Also flowing from God’s simplicity is His perfect goodness entailing justice and moral perfection. Because evil is not an attribute, but rather a flaw or deficiency in someone’s moral character, then God’s goodness is an essential aspect of His divine simplicity, as an infinite being lacks nothing and cannot be deficient. This also entails the act of self-gift (love) which flows from God’s triune nature as each person of the Trinity is eternally giving to the others.
- Omnipotence: God’s omnipotence denotes His possession of unlimited power and control over all things, wielding supreme authority.
- Omniscience: God’s omniscience signifies His perfect knowledge and understanding of everything. He comprehends all things past, present, and future, and nothing is hidden from His awareness.
- Omnipresence: God’s omnipresence refers to His presence everywhere, transcending the boundaries of space and time. He exists fully and completely in all places simultaneously.
- Infinite & Eternal: God’s infinity does not refer to an infinite number of thoughts or endless spatial extension, but rather signifies the absence of limits. He exists as an eternal being, beyond the constraints of time, without a beginning or end. God’s timelessness stands in contrast to human temporal experience, where we perceive time in a linear fashion with past, present, and future. For God, all moments coexist simultaneously in an eternal “now,” and He comprehends the entirety of time from its inception to its conclusion. His act of creation does not involve entering into time, but rather bringing time and the universe into existence.
- Immanence: Despite being transcendent and existing outside of time, God remains continuously present within the fabric of reality. His immanence is demonstrated by His active sustenance and interaction with His creation. This eternal creative activity establishes an intimate relationship between God and His creatures, showcasing their perpetual dependence on Him.
- Immutability & Impassability: Because God is outside of time, which is simply a measurement of change within creation, God possesses an unchangeable nature, remaining constant and consistent in His attributes. Because emotion implies changing between states of more or less perfection, God is also impassable, meaning He does not undergo emotional changes or suffer any alteration due to His unchangable perfection.
The Bible is full of metaphorical language, which is used to help engage our understanding of God.
Approaching biblical metaphors about God with a literal interpretation can lead to a superficial understanding of profound spiritual truths and limit our grasp of the divine’s depth and complexity. The Bible uses various literary devices, including figurative language, metaphors, and allegories, to convey deep spiritual and moral truths. Taking these metaphors literally may lead to misunderstandings and oversimplifications of complex theological concepts.
Throughout history, religious scholars and theologians have recognized the importance of interpreting biblical texts, including metaphors, with consideration of their context, literary genre, and theological implications. Embracing a more nuanced and symbolic interpretation allows for a deeper and richer understanding of the scriptures.
While the Bible uses various metaphors and anthropomorphic language to describe God, there are also verses that emphasize God’s nature as a pure spirit, transcending physical form. Verses like John 4:24, 1 Timothy 1:17, Colossians 1:15, 1 John 1:5, Exodus 33:20, Isaiah 55:8-9, and Psalm 139:7-8 highlight God’s immaterial and invisible nature, emphasizing that God exists as a pure spirit.
When the Bible describes God with emotions, such as anger, regret, or pleasure, these are metaphors describing how humans relate to God, not how God relates to us. As an eternal and perfect being, God’s nature does not change, and nothing can surprise or overwhelm the infinite act of being. Positing that God experiences emotion implies that He can change from a more or less perfect state. Understanding these phrases as metaphors in their symbolic context helps to avoid implying changes or imperfections in God’s nature.
“God transcends all creatures. We must therefore continually purify our language of everything in it that is limited, image-bound or imperfect, if we are not to confuse our image of God—”the inexpressible, the incomprehensible, the invisible, the ungraspable”—with our human representations. Our human words always fall short of the mystery of God” (C.C.C. 42).
“God is spirit, and his worshipers must worship in the Spirit and in truth.”
1 Timothy 1:17:
“To the King of the ages, immortal, invisible, the only God, be honor and glory forever and ever. Amen.”
“The Son is the image of the invisible God, the firstborn over all creation.”
1 John 1:5:
“This is the message we have heard from him and declare to you: God is light; in him, there is no darkness at all.”
“But,” he said, “you cannot see my face, for no one may see me and live.”
“For my thoughts are not your thoughts, neither are your ways my ways,” declares the Lord. “As the heavens are higher than the earth, so are my ways higher than your ways and my thoughts than your thoughts.”
“Where can I go from your Spirit? Where can I flee from your presence? If I go up to the heavens, you are there; if I make my bed in the depths, you are there.”
“Go therefore and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit.”
2 Corinthians 13:14:
“The grace of the Lord Jesus Christ, the love of God, and the communion of the Holy Spirit be with all of you.”
“how much more will the blood of Christ, who through the eternal Spirit offered himself without blemish to God, purify our conscience from dead works to worship the living God!”
“And I will ask the Father, and he will give you another Advocate, to be with you forever.”
“For this reason the Jews were seeking all the more to kill him, because he was not only breaking the sabbath, but was also calling God his own Father, thereby making himself equal to God.”
“He is the image of the invisible God, the firstborn of all creation; for in him all things in heaven and on earth were created, things visible and invisible, whether thrones or dominions or rulers or powers—all things have been created through him and for him. He himself is before all things, and in him all things hold together. He is the head of the body, the church; he is the beginning, the firstborn from the dead, so that he might come to have first place in everything. For in him all the fullness of God was pleased to dwell, and through him God was pleased to reconcile to himself all things, whether on earth or in heaven, by making peace through the blood of his cross. And you who were once estranged and hostile in mind, doing evil deeds, he has now reconciled in his fleshly body through death, so as to present you holy and blameless and irreproachable before him.”
Church Father Quotes:
“After the foregoing instructions, baptize in the name of the Father, and of the Son, and of the Holy Spirit, in living [running] water. . . . If you have neither, pour water three times on the head, in the name of the Father, and of the Son, and of the Holy Spirit” (Didache 7:1 [A.D. 70]).
“[T]o the Church at Ephesus in Asia . . . chosen through true suffering by the will of the Father in Jesus Christ our God” (Letter to the Ephesians 1 [A.D. 110]).
“For our God, Jesus Christ, was conceived by Mary in accord with God’s plan: of the seed of David, it is true, but also of the Holy Spirit” (ibid., 18:2).
“We will prove that we worship him reasonably; for we have learned that he is the Son of the true God himself, that he holds a second place, and the Spirit of prophecy a third. For this they accuse us of madness, saying that we attribute to a crucified man a place second to the unchangeable and eternal God, the Creator of all things; but they are ignorant of the mystery which lies therein” (First Apology 13:5–6 [A.D. 151]).
“It is the attribute of God, of the most high and almighty and of the living God, not only to be everywhere, but also to see and hear all; for he can in no way be contained in a place. . . . The three days before the luminaries were created are types of the Trinity: God, his Word, and his Wisdom” (To Autolycus 2:15 [A.D. 181]).
“For the Church, although dispersed throughout the whole world even to the ends of the earth, has received from the apostles and from their disciples the faith in one God, the Father Almighty . . . and in one Jesus Christ, the Son of God, who became flesh for our salvation; and in the Holy Spirit” (Against Heresies 1:10:1 [A.D. 189]).
“We do indeed believe that there is only one God, but we believe that under this dispensation, or, as we say, oikonomia, there is also a Son of this one only God, his Word, who proceeded from him and through whom all things were made and without whom nothing was made. . . . We believe he was sent down by the Father, in accord with his own promise, the Holy Spirit, the Paraclete, the sanctifier of the faith of those who believe in the Father and the Son, and in the Holy Spirit” (Against Praxeas 2 [A.D. 216]).
“And at the same time the mystery of the oikonomia is safeguarded, for the unity is distributed in a Trinity. Placed in order, the three are the Father, Son, and Spirit. They are three, however, not in condition, but in degree; not in being, but in form; not in power, but in kind; of one being, however, and one condition and one power, because he is one God of whom degrees and forms and kinds are taken into account in the name of the Father, and of the Son, and of the Holy Spirit” (ibid.).
“Keep always in mind the rule of faith which I profess and by which I bear witness that the Father and the Son and the Spirit are inseparable from each other, and then you will understand what is meant by it. Observe now that I say the Father is other [distinct], the Son is other, and the Spirit is other. This statement is wrongly understood by every uneducated or perversely disposed individual, as if it meant diversity and implied by that diversity a separation of Father, Son, and Holy Spirit” (ibid., 9).
“Thus the connection of the Father in the Son, and of the Son in the Paraclete, produces three coherent persons, who are yet distinct one from another. These three are, one essence, not one person, as it is said, ‘I and my Father are one’ [John 10:30], in respect of unity of being not singularity of number” (ibid., 25).
“For we do not hold that which the heretics imagine: that some part of the being of God was converted into the Son, or that the Son was procreated by the Father from non-existent substances, that is, from a being outside himself, so that there was a time when he [the Son] did not exist” (The Fundamental Doctrines 4:4:1 [A.D. 225]).
“For it is the Trinity alone which exceeds every sense in which not only temporal but even eternal may be understood. It is all other things, indeed, which are outside the Trinity, which are to be measured by time and ages” (ibid.).
“The Word alone of this God is from God himself, wherefore also the Word is God, being the being of God” (Refutation of All Heresies 10:29 [A.D. 228]).
“Next, then, I may properly turn to those who divide and cut apart and destroy the most sacred proclamation of the Church of God, making of it [the Trinity], as it were, three powers, distinct substances, and three godheads. . . . [Some heretics] proclaim that there are in some way three gods, when they divide the sacred unity into three substances foreign to each other and completely separate” (Letter to Dionysius of Alexandria 1 [A.D. 262]).
“Therefore, the divine Trinity must be gathered up and brought together in one, a summit, as it were, I mean the omnipotent God of the universe. . . . It is blasphemy, then, and not a common one but the worst, to say that the Son is in any way a handiwork [creature]. . . . But if the Son came into being [was created], there was a time when these attributes did not exist; and, consequently, there was a time when God was without them, which is utterly absurd” (ibid., 1–2).
“Neither, then, may we divide into three godheads the wonderful and divine unity. . . . Rather, we must believe in God, the Father Almighty; and in Christ Jesus, his Son; and in the Holy Spirit; and that the Word is united to the God of the universe. ‘For,’ he says, ‘The Father and I are one,’ and ‘I am in the Father, and the Father in me’” (ibid., 3).
“There is one God. . . . There is a perfect Trinity, in glory and eternity and sovereignty, neither divided nor estranged. Wherefore there is nothing either created or in servitude in the Trinity; nor anything superinduced, as if at some former period it was non-existent, and at some later period it was introduced. And thus neither was the Son ever wanting to the Father, nor the Spirit to the Son; but without variation and without change, the same Trinity abides ever” (Declaration of Faith [A.D. 265]).
“Hymns, with Revelation and the Psalms of God [Patrick] sings, and does expound the same for the edifying of God’s people. This law he holds in the Trinity of the sacred Name and teaches one being in three persons” (Hymn in Praise of St. Patrick 22 [A.D. 444]).
“I bind to myself today the strong power of an invocation of the Trinity—the faith of the Trinity in unity, the Creator of the universe” (The Breastplate of St. Patrick 1 [A.D. 447]).
“[T]here is no other God, nor has there been heretofore, nor will there be hereafter, except God the Father unbegotten, without beginning, from whom is all beginning, upholding all things, as we say, and his Son Jesus Christ, whom we likewise to confess to have always been with the Father—before the world’s beginning. . . . Jesus Christ is the Lord and God in whom we believe . . . and who has poured out on us abundantly the Holy Spirit . . . whom we confess and adore as one God in the Trinity of the sacred Name” (Confession of St. Patrick 4 [A.D. 452]).
“All the Catholic interpreters of the divine books of the Old and New Testaments whom I have been able to read, who wrote before me about the Trinity, which is God, intended to teach in accord with the Scriptures that the Father and the Son and the Holy Spirit are of one and the same substance constituting a divine unity with an inseparable equality; and therefore there are not three gods but one God, although the Father begot the Son, and therefore he who is the Son is not the Father; and the Holy Spirit is neither the Father nor the Son but only the Spirit of the Father and of the Son, himself, too, coequal to the Father and to the Son and belonging to the unity of the Trinity” (The Trinity1:4:7 [A.D. 408]).
“See, in short you have it that the Father is one, the Son another, and the Holy Spirit another; in Person, each is other, but in nature they are not other. In this regard he says: ‘The Father and I, we are one’ (John 10:30). He teaches us that onerefers to their nature, and we are to their Persons. In like manner it is said: ‘There are three who bear witness in heaven, the Father, the Word, and the Spirit; and these three are one’ (1 John 5:7)” (The Trinity 4:1–2 [c. A.D. 515]).
“But in the one true God and Trinity it is naturally true not only that God is one but also that he is a Trinity, for the reason that the true God himself is a Trinity of Persons and one in nature. Through this natural unity the whole Father is in the Son and in the Holy Spirit, and the whole Holy Spirit, too, is in the Father and in the Son. None of these is outside any of the others; because no one of them precedes any other of them in eternity or exceeds any other in greatness, or is superior to any other in power” (The Rule of Faith 4 [c. A.D. 523).
“And further, my brethren, if the Lord [Jesus] endured to suffer for our soul, he being the Lord of all the world, to whom God said at the foundation of the world, ‘Let us make man after our image, and after our likeness,’ understand how it was that he endured to suffer at the hand of men” (Letter of Barnabas 5 [A.D. 74], emphasis added).
“Jesus Christ . . . was with the Father before the beginning of time, and in the end was revealed. . . . Jesus Christ . . . came forth from one Father and is with and has gone to one [Father]. . . . [T]here is one God, who has manifested himself by Jesus Christ his Son, who is his eternal Word, not proceeding forth from silence, and who in all things pleased him that sent him” (Letter to the Magnesians 6–8 [A.D. 110], emphasis added).
“God speaks in the creation of man with the very same design, in the following words: ‘Let us make man after our image and likeness.’ . . . I shall quote again the words narrated by Moses himself, from which we can indisputably learn that [God] conversed with someone numerically distinct from himself and also a rational being. . . . But this offspring who was truly brought forth from the Father, was with the Father before all the creatures, and the Father communed with him” (Dialogue with Trypho the Jew 62 [A.D. 155]).
“[The Father] sent the Word that he might be manifested to the world. . . . This is he who was from the beginning, who appeared as if new, and was found old. . . . This is he who, being from everlasting, is today called the Son” (Letter to Diognetus 11 [A.D. 160], emphasis added).
“It was not angels, therefore, who made us nor who formed us, neither had angels power to make an image of God, nor anyone else. . . . For God did not stand in need of these in order to accomplish what he had himself determined with himself beforehand should be done, as if he did not possess his own hands. For with him [the Father] were always present the Word and Wisdom, the Son and the Spirit, by whom and in whom, freely and spontaneously, he made all things, to whom also he speaks, saying, ‘Let us make man in our image and likeness’ [Gen. 1:26]” (Against Heresies 4:20:1 [A.D. 189], emphasis added).
“While keeping to this demurrer always, there must, nevertheless, be place for reviewing for the sake of the instruction and protection of various persons. . . . This is especially so in the case of the present heresy [Sabellianism], which considers itself to have the pure truth when it supposes that one cannot believe in the one only God in any way other than by saying that Father, Son, and Spirit are the selfsame person. As if one were not all . . . through the unity of substance” (Against Praxeas 2:3–4 [A.D. 216]).
“Keep always in mind the rule of faith which I profess and by which I bear witness that the Father and the Son and the Spirit are inseparable from each other, and then you will understand what is meant by it. Observe, now, that I say the Father is other [distinct], and the Son is other, and the Spirit is other. . . . I say this, however, out of necessity, since they contend that the Father and the Son and the Spirit are the selfsame person” (ibid. 9:1).
“[The Trinity] is a Trinity not merely in name or in a figurative manner of speaking; rather, it is a Trinity in truth and in actual existence. Just as the Father is he that is, so also his Word is one that is and is God over all. And neither is the Holy Spirit nonexistent but actually exists and has true being” (Letters to Serapion 1:28 [A.D. 359]).
“They [the Father and the Son] are one, not as one thing now divided into two, but really constituting only one, nor as one thing twice named, so that the same becomes at one time the Father and at another his own Son. This latter is what Sabellius held, and he was judged a heretic. On the contrary, they are two, because the Father is Father and is not his own Son, and the Son is Son and not his own Father” (Discourses Against the Arians 3:4 [A.D. 360]).