The Christian doctrine of the Trinity (Latin: Trinitas, lit. 'triad', from trinus, "threefold") holds that God is three consubstantial persons or hypostases—the Father, the Son (Jesus Christ), and the Holy Spirit—as "one God in three Divine Persons". The three persons are distinct, yet are one "substance, essence or nature". In this context, a "nature" is what one is, whereas a "person" is who one is.
According to this central mystery of most Christian faiths, there is only one God in three persons: while distinct from one another in their relations of origin (as the Fourth Lateran Council declared, "it is the Father who generates, the Son who is begotten, and the Holy Spirit who proceeds") and in their relations with one another, they are stated to be one in all else, co-equal, co-eternal and consubstantial, and each is God, whole and entire". Accordingly, the whole work of creation and grace is seen as a single operation common to all three divine persons, in which each shows forth what is proper to him in the Trinity, so that all things are "from the Father", "through the Son" and "in the Holy Spirit".
While the Fathers of the Church saw even Old Testament elements such as the appearance of three men to Abraham in Book of Genesis, chapter 18, as foreshadowings of the Trinity, it was the New Testament that they saw as a basis for developing the concept of the Trinity. The most influential of the New Testament texts seen as implying the teaching of the Trinity was , which mandated baptizing "in the name of the Father, and of the Son, and of the Holy Spirit". Reflection, proclamation and dialogue led to the formulation of the doctrine that was felt to correspond to the data in the Bible. The simplest outline of the doctrine was formulated in the 4th century, largely in terms of rejection of what was considered not to be consonant with general Christian belief. Further elaboration continued in the succeeding centuries.
Scripture contains neither the word Trinity, nor an expressly formulated doctrine of the Trinity. Rather, according to the Christian theology, it "bears witness to" the activity of a God who can only be understood in Trinitarian terms. The doctrine did not take its definitive shape until late in the fourth century. During the intervening period, various tentative solutions, some more and some less satisfactory, were proposed. Trinitarianism contrasts with nontrinitarian positions which include Binitarianism (one deity in two persons, or two deities), Unitarianism (one deity in one person, analogous to Jewish interpretation of the Shema and Muslim belief in Tawhid), Oneness Pentecostalism or Modalism (one deity manifested in three separate aspects).
The word "trinity" is derived from Latin trinitas, meaning "the number three, a triad". This abstract noun is formed from the adjective trinus (three each, threefold, triple), as the word unitas is the abstract noun formed from unus (one).
The corresponding word in Greek is Τριάς, meaning "a set of three" or "the number three". The first recorded use of this Greek word in Christian theology was by Theophilus of Antioch in about 170. He wrote:
In like manner also the three days which were before the luminaries, are types of the Trinity [Τριάδος], of God, and His Word, and His wisdom. And the fourth is the type of man, who needs light, that so there may be God, the Word, wisdom, man.
Tertullian, a Latin theologian who wrote in the early 3rd century, is credited as being the first to use the Latin words "Trinity", "person" and "substance" to explain that the Father, Son, and Holy Spirit are "one in essence—not one in Person".
The Ante-Nicene Fathers asserted Christ's deity and spoke of "Father, Son and Holy Spirit", even though their language is not that of the traditional doctrine as formalised in the fourth century. Trinitarians view these as elements of the codified doctrine. Ignatius of Antioch provides early support for the Trinity around 110, exhorting obedience to "Christ, and to the Father, and to the Spirit". Justin Martyr (AD 100–c. 165) also writes, "in the name of God, the Father and Lord of the universe, and of our Saviour Jesus Christ, and of the Holy Spirit". The first of the early church fathers to be recorded using the word "Trinity" was Theophilus of Antioch writing in the late 2nd century. He defines the Trinity as God, His Word (Logos) and His Wisdom (Sophia) in the context of a discussion of the first three days of creation. The first defence of the doctrine of the Trinity was in the early 3rd century by the early church father Tertullian. He explicitly defined the Trinity as Father, Son, and Holy Spirit and defended the Trinitarian theology against the "Praxean" heresy. St. Justin and Clement of Alexandra used the Trinity in their doxologies and St. Basil likewise, in the evening lighting of lamps.
Another early, and already more philosophic, formulation of the Trinity (again without usage of that term) is attributed to the Gnostic teacher Valentinus (lived c.100 – c.160), who according to the fourth century theologian Marcellus of Ancyra, was “the first to devise the notion of three subsistent entities (hypostases), in a work that he entitled On the Three Natures”. The highly allegorical exegesis of the Valentinian school inclined it to interpret the relevant scriptural passages as affirming a Divinity that, in some manner, is threefold. The Valentinian Gospel of Phillip, which dates to approximately the time of Tertullian, upholds the Trinitarian formula. Whatever his influence on the later fully formed doctrine may have been, however, Valentinus' school is rejected as heretical by orthodox Christians.
Although there is much debate as to whether the beliefs of the Apostles were merely articulated and explained in the Trinitarian Creeds, or were corrupted and replaced with new beliefs, all scholars recognize that the Creeds themselves were created in reaction to disagreements over the nature of the Father, Son, and Holy Spirit. These controversies, however, were great and many, and took some centuries to be resolved.
Of these controversies, the most significant developments were articulated in the first four centuries by the Church Fathers in reaction to Adoptionism, Sabellianism, and Arianism. Adoptionism was the belief that Jesus was an ordinary man, born of Joseph and Mary, who became the Christ and Son of God at his baptism. In 269, the Synods of Antioch condemned Paul of Samosata for his Adoptionist theology, and also condemned the term homoousios (ὁμοούσιος, "of the same being") in the sense he used it.
Sabellianism taught that the Father, the Son, and the Holy Spirit are essentially one and the same, the difference being simply verbal, describing different aspects or roles of a single being. For this view Sabellius was excommunicated for heresy in Rome c. 220.
In the fourth century, Arius, as traditionally understood, taught that the Father existed prior to the Son who was not, by nature, God but rather a changeable creature who was granted the dignity of becoming "Son of God". In 325, the Council of Nicaea adopted the Nicene Creed which described Christ as "God of God, Light of Light, very God of very God, begotten, not made, being of one substance with the Father". The creed used the term homoousios (of one substance) to define the relationship between the Father and the Son. After more than fifty years of debate, homoousios was recognised as the hallmark of orthodoxy, and was further developed into the formula of "three persons, one being".
Athanasius (293–373), who was present at the Council as one of the Bishop of Alexandria's assistants, stated that the bishops were forced to use this terminology, which is not found in Scripture, because the biblical phrases that they would have preferred to use were claimed by the Arians to be capable of being interpreted in what the bishops considered to be a heretical sense. Moreover, the meanings of "ousia" and "hypostasis" overlapped then, so that "hypostasis" for some meant "essence" and for others "person".
The Confession of the Council of Nicaea said little about the Holy Spirit. The doctrine of the divinity and personality of the Holy Spirit was developed by Athanasius in the last decades of his life. He defended and refined the Nicene formula. By the end of the 4th century, under the leadership of Basil of Caesarea, Gregory of Nyssa, and Gregory of Nazianzus (the Cappadocian Fathers), the doctrine had reached substantially its current form.
Gregory of Nazianzus would say of the Trinity, "No sooner do I conceive of the One than I am illumined by the splendour of the Three; no sooner do I distinguish Three than I am carried back into the One. When I think of any of the Three, I think of Him as the Whole, and my eyes are filled, and the greater part of what I am thinking escapes me. I cannot grasp the greatness of that One so as to attribute a greater greatness to the rest. When I contemplate the Three together, I see but one torch, and cannot divide or measure out the undivided light."
Devotion to the Trinity centered in the French monasteries at Tours and Aniane where Saint Benedict dedicated the abbey church to the Trinity in 872. Feast Days were not instituted until 1091 at Cluny and 1162 at Canterbury and papal resistance continued until 1331.
Trinitarian baptismal formula
In the synoptic Gospels the baptism of Jesus is often interpreted as a manifestation of all three persons of the Trinity: "And when Jesus was baptized, he went up immediately from the water, and behold, the heavens were opened and he saw the spirit of God descending like a dove, and alighting on him; and lo, a voice from heaven, saying, 'This is my beloved Son, with whom I am well pleased.'" Baptism is generally conferred with the Trinitarian formula, "in the name of the Father, and of the Son, and of the Holy Spirit". Trinitarians identify this name with the Christian faith into which baptism is an initiation, as seen for example in the statement of Basil the Great (330–379): "We are bound to be baptized in the terms we have received, and to profess faith in the terms in which we have been baptized." The First Council of Constantinople (381) also says, "This is the Faith of our baptism that teaches us to believe in the Name of the Father, of the Son and of the Holy Spirit. According to this Faith there is one Godhead, Power, and Being of the Father, of the Son, and of the Holy Spirit." may be taken to indicate that baptism was associated with this formula from the earliest decades of the Church's existence.
Nontrinitarian groups, such as Oneness Pentecostals, demur from the Trinitarian view on baptism. For them, the formula in the Book of Acts defines and affirms that all other considerations, alike, are to be used in the name of Jesus Christ. For this reason, they often focus on the baptisms in Acts. Those who place great emphasis on the baptisms in Acts often likewise question the authenticity of in its present form. Most scholars of New Testament textual criticism accept the authenticity of the passage, since there are no variant manuscripts regarding the formula, and the extant form of the passage is attested in the Didache and other patristic works of the 1st and 2nd centuries: Ignatius, Tertullian, Hippolytus, Cyprian, and Gregory Thaumaturgus.
Commenting on , Gerhard Kittel states:
This threefold relation [of Father, Son and Spirit] soon found fixed expression in the triadic formulae in and in . The form is first found in the baptismal formula in ; Did., 7. 1 and 3....[I]t is self-evident that Father, Son and Spirit are here linked in an indissoluble threefold relationship.
Christianity, having emerged from Judaism, is a monotheistic religion. Never in the New Testament does the Trinitarian concept become a "tritheism" (three Gods) nor even two. God is one, and that God is a single being is strongly declared in the Bible:
- The Shema of the Hebrew Scriptures: "Hear, O Israel: the LORD our God, the LORD is one."
- The first of the Ten Commandments—"Thou shalt have no other gods before me."
- And "Thus saith the LORD the King of Israel and his redeemer the LORD of hosts: I am the first and I am the last; and beside me there is no God."
- In the New Testament: "The LORD our God is one."
In the Trinitarian view, the Father and the Son and the Holy Spirit share the one essence, substance or being. The central and crucial affirmation of Christian faith is that there is one savior, God, and one salvation, manifest in Jesus Christ, to which there is access only because of the Holy Spirit. The God of the Old Testament is still the same as the God of the New. In Christianity, statements about a single God are intended to distinguish the Hebraic understanding from the polytheistic view, which see divine power as shared by several beings, beings which can and do disagree and have conflicts with each other.
One God as three persons
In Trinitarian doctrine, God exists as three persons or hypostases, but is one being, having a single divine nature. The members of the Trinity are co-equal and co-eternal, one in essence, nature, power, action, and will. As stated in the Athanasian Creed, the Father is uncreated, the Son is uncreated, and the Holy Spirit is uncreated, and all three are eternal without beginning. "The Father and the Son and the Holy Spirit" are not names for different parts of God, but one name for God because three persons exist in God as one entity. They cannot be separate from one another. Each person is understood as having the identical essence or nature, not merely similar natures.
For Trinitarians, emphasis in Genesis 1:26 is on the plurality in the Deity, and in 1:27 on the unity of the divine Essence. A possible interpretation of Genesis 1:26 is that God's relationships in the Trinity are mirrored in man by the ideal relationship between husband and wife, two persons becoming one flesh, as described in Eve's creation later in the next chapter.
Perichoresis (from Greek, "going around", "envelopment") is a term used by some theologians to describe the relationship among the members of the Trinity. The Latin equivalent for this term is circumincessio. This concept refers for its basis to , where Jesus is instructing the disciples concerning the meaning of his departure. His going to the Father, he says, is for their sake; so that he might come to them when the "other comforter" is given to them. Then, he says, his disciples will dwell in him, as he dwells in the Father, and the Father dwells in him, and the Father will dwell in them. This is so, according to the theory of perichoresis, because the persons of the Trinity "reciprocally contain one another, so that one permanently envelopes and is permanently enveloped by, the other whom he yet envelopes". (Hilary of Poitiers, Concerning the Trinity 3:1).
Perichoresis effectively excludes the idea that God has parts, but rather is a simple being. It also harmonizes well with the doctrine that the Christian's union with the Son in his humanity brings him into union with one who contains in himself, in the Apostle Paul's words, "all the fullness of deity" and not a part. (See also: Divinization (Christian)). Perichoresis provides an intuitive figure of what this might mean. The Son, the eternal Word, is from all eternity the dwelling place of God; he is the "Father's house", just as the Son dwells in the Father and the Spirit; so that, when the Spirit is "given", then it happens as Jesus said, "I will not leave you as orphans; for I will come to you."
According to the words of Jesus, married persons are in some sense no longer two but are joined into one. Therefore, Orthodox theologians also see the marriage relationship between a man and a woman to be an example of this sacred union. "Therefore shall a man leave his father and his mother, and shall cleave unto his wife: and they shall be one flesh." Gen. 2:24. "Wherefore they are no more twain but one flesh. What therefore God hath joined together, let no man put asunder." Matt. 19: 6.
Eternal generation and procession
Trinitarianism affirms that the Son is "begotten" (or "generated") of the Father and that the Spirit "proceeds" from the Father, but the Father is "neither begotten nor proceeds". The argument over whether the Spirit proceeds from the Father alone, or from the Father and the Son, was one of the catalysts of the Great Schism, in this case concerning the Western addition of the Filioque clause to the Nicene Creed. The Roman Catholic Church teaches that, in the sense of the Latin verb procedere (which does not have to indicate ultimate origin and is therefore compatible with proceeding through), but not in that of the Greek verb ἐκπορεύεσθαι (which implies ultimate origin), the Spirit "proceeds" from the Father and the Son, and the Eastern Orthodox Church, which teaches that the Spirit "proceeds" from the Father alone, has made no statement on the claim of a difference in meaning between the two words, one Greek and one Latin, both of which are translated as "proceeds". The Eastern Orthodox Churches object to the Filioque clause on ecclesiological and theological grounds, holding that "from the Father" means "from the Father alone".
This language is often considered difficult because, if used regarding humans or other created things, it would imply time and change; when used here, no beginning, change in being, or process within time is intended and is excluded. The Son is generated ("born" or "begotten"), and the Spirit proceeds, eternally. Augustine of Hippo explains, "Thy years are one day, and Thy day is not daily, but today; because Thy today yields not to tomorrow, for neither does it follow yesterday. Thy today is eternity; therefore Thou begat the Co-eternal, to whom Thou saidst, 'This day have I begotten Thee.'"
Most Protestant groups that use the creed also include the Filioque clause. Its controversial use is addressed in several confessions: the Westminster Confession 2:3, the London Baptist Confession 2:3, and the Lutheran Augsburg Confession 1:1–6.
Economic and immanent Trinity
The economic Trinity refers to the acts of the triune God with respect to the creation, history, salvation, the formation of the Church, the daily lives of believers, etc. and describes how the Trinity operates within history in terms of the roles or functions performed by each person of the Trinity—God's relationship with creation. The ontological (or essential or immanent) Trinity speaks of the interior life of the Trinity—the reciprocal relationships of Father, Son, and Spirit to each other without reference to God's relationship with creation.
The ancient Nicene theologians argued that everything the Trinity does is done by Father, Son, and Spirit working in unity with one will. The three persons of the Trinity always work inseparably, for their work is always the work of the one God. The Son's will cannot be different from the Father's because it is the Father's. They have but one will as they have but one being. Otherwise they would not be one God. According to Phillip Cary, if there were relations of command and obedience between the Father and the Son, there would be no Trinity at all but rather three gods. On this point St. Basil observes "When then He says, 'I have not spoken of myself', and again, 'As the Father said unto me, so I speak', and 'The word which ye hear is not mine, but [the Father's] which sent me', and in another place, 'As the Father gave me commandment, even so I do', it is not because He lacks deliberate purpose or power of initiation, nor yet because He has to wait for the preconcerted key-note, that he employs language of this kind. His object is to make it plain that His own will is connected in indissoluble union with the Father. Do not then let us understand by what is called a 'commandment' a peremptory mandate delivered by organs of speech, and giving orders to the Son, as to a subordinate, concerning what He ought to do. Let us rather, in a sense befitting the Godhead, perceive a transmission of will, like the reflexion of an object in a mirror, passing without note of time from Father to Son."
In explaining why the Bible speaks of the Son as being subordinate to the Father, the great theologian Athanasius argued that scripture gives a "double account" of the son of God—one of his temporal and voluntary subordination in the incarnation, and the other of his eternal divine status. For Athanasius, the Son is eternally one in being with the Father, temporally and voluntarily subordinate in his incarnate ministry. Such human traits, he argued, were not to be read back into the eternal Trinity.
Like Athanasius, the Cappadocian Fathers also insisted there was no economic inequality present within the Trinity. As Basil wrote: "We perceive the operation of the Father, Son, and Holy Spirit to be one and the same, in no respect showing differences or variation; from this identity of operation we necessarily infer the unity of nature."
Augustine also rejected an economic hierarchy within the Trinity. He claimed that the three persons of the Trinity "share the inseparable equality one substance present in divine unity". Because the three persons are one in their inner life, this means that for Augustine their works in the world are one. For this reason, it is an impossibility for Augustine to speak of the Father commanding and the Son obeying as if there could be a conflict of wills within the eternal Trinity.
John Calvin also spoke at length about the doctrine of the Trinity. Like Athanasius and Augustine before him, he concluded that prescribed how scripture was to be read correctly. For him the Son's obedience is limited to the incarnation and is indicative of his true humanity assumed for human salvation.
Much of this work is summed up in the Athanasian Creed. This creed stresses the unity of the Trinity and the equality of the persons. It ascribes equal divinity, majesty, and authority to all three persons. All three are said to be "almighty" and "Lord" (no subordination in authority; "none is before or after another" (no hierarchical ordering); and "none is greater, or less than another" (no subordination in being or nature)).
Catholic theologian Karl Rahner went so far as to say:
The "economic" Trinity is the "immanent" Trinity and the "immanent" Trinity is the "economic" Trinity.
Richard Rubinstein says that Emperor Constantine and his advisor Hosius of Cordoba were aware of the usefulness of having a divinely ordained church in which the church authority, and not the individual, were able to determine individual salvation, and threw their support toward the homoousion Trinitarian formula. Constantine suggested the initial use of the term homoousios at the Council of Nicaea. Constantine later changed his view about the Nicene formula and supported the bishops who rejected it, as did several of his successors, the first emperor to be baptized in the Nicene faith being Theodosius the Great, emperor from 379 to 395.
From the Old Testament the early church retained the conviction that God is one. The New Testament does not use the word Τριάς (Trinity) nor explicitly teach the Nicene Trinitarian doctrine, but it contains several passages that use twofold and threefold patterns to speak of God. Binitarian passages include Rom. 8:11, 2 Cor. 4:14, Galatians 1:1, Eph. 1:20, 1 Tim. 1:2, 1 Pet. 1:21, and 2 John 1:13. Passages which refer to the Godhead with a threefold pattern include Matt. 28:19, 1 Cor. 6:11 and 12:4ff., Gal. 3:11–14, Heb. 10:29, and 1 Pet. 1:2. These passages provided the material with which Christians would develop doctrines of the Trinity. Reflection by early Christians on passages such as the Great Commission: "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" and Paul the Apostle's blessing: "The grace of the Lord Jesus Christ and the love of God and the fellowship of the Holy Spirit be with you all", while at the same time the Jewish Shema Yisrael: "Hear, O Israel: the Lord our God, the Lord is one" led the early Christians to question how the Father, Son, and Holy Spirit are "one". Later, the diverse references to God, Jesus, and the Spirit found in the New Testament were systematized into a Trinity—one God subsisting in three persons and one substance—to combat heretical tendencies of how the three are related and to defend the church against charges of worshiping two or three gods.
Some scholars dispute the idea that support for the Trinity can be found in the Bible, and argue that the doctrine is the result of theological interpretations rather than sound exegesis of scripture. The concept was expressed in early writings from the beginning of the 2nd century forward, and other scholars hold that the way the New Testament repeatedly speaks of the Father, the Son, and the Holy Spirit is such as to require one to accept a Trinitarian understanding.
The Comma Johanneum, , is a disputed text which states: "For there are three that bear record in heaven, the Father, the Word, and the Holy Ghost: and these three are one." However, this passage is not considered to be part of the genuine text, and most scholars agree that the phrase was a gloss.
Jesus as God
The Gospel of John has been seen as especially aimed at emphasizing Jesus' divinity, presenting Jesus as the Logos, pre-existent and divine, from its first words, "In the beginning was the Word, and the Word was with God, and the Word was God." The Gospel of John ends with Thomas's declaration that he believed Jesus was God, "My Lord and my God!" There is no significant tendency among modern scholars to deny that John 1:1 and John 20:28 identify Jesus with God. John also portrays Jesus as the agent of creation of the universe.
There are also a few possible biblical supports for the divinity of Jesus found in the Synoptic Gospels. The Gospel of Matthew, for example, quotes Jesus as saying, "All things have been handed over to me by my Father." This is similar to John, who wrote that Jesus said, "All that the Father has is mine." These verses have been quoted to defend the omnipotence of Christ, having all power, as well as the omniscience of Christ, having all wisdom.
Expressions also in the Pauline epistles have been interpreted as attributing divinity to Jesus. They include: "For by him all things were created: things in heaven and on earth, visible and invisible, whether thrones or powers or rulers or authorities; all things were created by him and for him" and "For in Christ all the fullness of the Deity lives in bodily form", and in Paul the Apostle's claim to have been "sent not from men nor by man, but by Jesus Christ and God the Father".
Some have suggested that John presents a hierarchy when he quotes Jesus as saying, "The Father is greater than I", a statement which was appealed to by nontrinitarian groups such as Arianism. However, Church Fathers such as Augustine of Hippo argued this statement was to be understood as Jesus speaking in the form of a man.
Holy Spirit as God
As the Arian controversy was dissipating, the debate moved from the deity of Jesus Christ to the equality of the Holy Spirit with the Father and Son. On one hand, the Pneumatomachi sect declared that the Holy Spirit was an inferior person to the Father and Son. On the other hand, the Cappadocian Fathers argued that the Holy Spirit was an equal person to the Father and Son.
Although the main text used in defense of the deity of the Holy Spirit was Matthew 28:19, Cappadocian Fathers such as Basil the Great argued from other verses such as "But Peter said, 'Ananias, why has Satan filled your heart to lie to the Holy Spirit and to keep back for yourself part of the proceeds of the land? While it remained unsold, did it not remain your own? And after it was sold, was it not at your disposal? Why is it that you have contrived this deed in your heart? You have not lied to men but to God.'"
Another passage the Cappadocian Fathers quoted from was "By the word of the Lord the heavens were made, and by the breath of his mouth all their host." According to their understanding, because "breath" and "spirit" in Hebrew are both "רוּחַ" ("ruach"), Psalm 33:6 is revealing the roles of the Son and Holy Spirit as co-creators. And since, according to them, because only the holy God can create holy beings such as the angels, the Son and Holy Spirit must be God.
Yet another argument from the Cappadocian Fathers to prove that the Holy Spirit is of the same nature as the Father and Son comes from "For who knows a person's thoughts except the spirit of that person, which is in him? So also no one comprehends the thoughts of God except the Spirit of God." They reasoned that this passage proves that the Holy Spirit has the same relationship to God as the spirit within us has to us.
The Cappadocian Fathers also quoted, "Do you not know that you are God's temple and that God's Spirit dwells in you?" and reasoned that it would be blasphemous for an inferior being to take up residence in a temple of God, thus proving that the Holy Spirit is equal with the Father and the Son.
They also combined "the servant does not know what his master is doing" with 1 Corinthians 2:11 in an attempt to show that the Holy Spirit is not the slave of God, and therefore his equal.
The Pneumatomachi contradicted the Cappadocian Fathers by quoting, "Are they not all ministering spirits sent out to serve for the sake of those who are to inherit salvation?" in effect arguing that the Holy Spirit is no different from other created angelic spirits. The Church Fathers disagreed, saying that the Holy Spirit is greater than the angels, since the Holy Spirit is the one who grants the foreknowledge for prophecy so that the angels could announce events to come.
The usage of the word "paraclete" (Greek: parakletos) for the Holy Spirit in , which can be translated as advocate, intercessor, counsellor or protector, and the Holy Spirit's essence and action characterized by truth, as all three persons of the Trinity are linked with truth (see v. 17), are seen as arguments that he is a divine person; especially that Jesus calls him another counsellor, in this way expressing that the Holy Spirit is similar to himself in regard to our counsel.
Old Testament parallels
In addition, the Old Testament has also been interpreted as foreshadowing the Trinity, by referring to God's word, his spirit, and Wisdom, as well as narratives such as the appearance of the three men to Abraham. However, it is generally agreed among Trinitarian Christian scholars that it would go beyond the intention and spirit of the Old Testament to correlate these notions directly with later Trinitarian doctrine.
Some Church Fathers believed that a knowledge of the mystery was granted to the prophets and saints of the Old Testament, and that they identified the divine messenger of ,, , and Wisdom of the sapiential books with the Son, and "the spirit of the Lord" with the Holy Spirit. Other Church Fathers, such as Gregory Nazianzen, argued in his Orations that the revelation was gradual, claiming that the Father was proclaimed in the Old Testament openly, but the Son only obscurely, because "it was not safe, when the Godhead of the Father was not yet acknowledged, plainly to proclaim the Son".
Genesis 18–19 has been interpreted by Christians as a Trinitarian text. The narrative has the Lord appearing to Abraham, who was visited by three men. Then in , "the two angels" visited Lot at Sodom. The interplay between Abraham on the one hand and the Lord/three men/the two angels on the other was an intriguing text for those who believed in a single God in three persons. Justin Martyr, and John Calvin similarly, interpreted it such that Abraham was visited by God, who was accompanied by two angels. Justin supposed that the God who visited Abraham was distinguishable from the God who remains in the heavens, but was nevertheless identified as the (monotheistic) God. Justin appropriated the God who visited Abraham to Jesus, the second person of the Trinity.
Augustine, in contrast, held that the three visitors to Abraham were the three persons of the Trinity. He saw no indication that the visitors were unequal, as would be the case in Justin's reading. Then in , two of the visitors were addressed by Lot in the singular: "Lot said to them, 'Not so, my lord.'" Augustine saw that Lot could address them as one because they had a single substance, despite the plurality of persons.
According to Swedenborg, the three angels which appeared to Abraham do represent the Trinity, but a Trinity of one being: the Divine Itself, the Divine Human and the Divine Proceeding. That one being is represented is indicated by the fact that they are referred to in the singular as Jehovah and Lord. The reason why only two of the angels went to visit Sodom and Gomorrah is that they represent the Divine Human and the Divine Proceeding, and to those aspects of the Divine belongs judgment, as Jesus declared that all judgment was entrusted by the Father to the Son. The three angels did indeed appear to Abraham as three men, but they are only a symbolic representation of the Trinity, which should not be taken literally as three distinct persons. In the Old Testament, Swedenborg finds the earliest direct reference to a Trine in the Divinity in the account of Moses' encounter with the Lord in Exodus which states, "And Jehovah passed by upon his face, and called, Jehovah, Jehovah, a God merciful and gracious."
Some Christians interpret the theophanies or appearances of the Angel of the Lord as revelations of a person distinct from God, who is nonetheless called God. This interpretation is found in Christianity as early as Justin Martyr and Melito of Sardis, and reflects ideas that were already present in Philo. The Old Testament theophanies were thus seen as Christophanies, each a "preincarnate appearance of the Messiah".
The Trinity is most commonly seen in Christian art with the Spirit represented by a dove, as specified in the Gospel accounts of the Baptism of Christ; he is nearly always shown with wings outspread. However depictions using three human figures appear occasionally in most periods of art.
The Father and the Son are usually differentiated by age, and later by dress, but this too is not always the case. The usual depiction of the Father as an older man with a white beard may derive from the biblical Ancient of Days, which is often cited in defense of this sometimes controversial representation. However, in Eastern Orthodoxy the Ancient of Days is usually understood to be God the Son, not God the Father (see below)—early Byzantine images show Christ as the Ancient of Days, but this iconography became rare. When the Father is depicted in art, he is sometimes shown with a halo shaped like an equilateral triangle, instead of a circle. The Son is often shown at the Father's right hand. He may be represented by a symbol—typically the Lamb (agnus dei) or a cross—or on a crucifix, so that the Father is the only human figure shown at full size. In early medieval art, the Father may be represented by a hand appearing from a cloud in a blessing gesture, for example in scenes of the Baptism of Christ. Later, in the West, the Throne of Mercy (or "Throne of Grace") became a common depiction. In this style, the Father (sometimes seated on a throne) is shown supporting either a crucifix or, later, a slumped crucified Son, similar to the Pietà (this type is distinguished in German as the Not Gottes) in his outstretched arms, while the Dove hovers above or in between them. This subject continued to be popular until the 18th century at least.
By the end of the 15th century, larger representations, other than the Throne of Mercy, became effectively standardised, showing an older figure in plain robes for the Father, Christ with his torso partly bare to display the wounds of his Passion, and the dove above or around them. In earlier representations both Father, especially, and Son often wear elaborate robes and crowns. Sometimes the Father alone wears a crown, or even a papal tiara.
Nontrinitarianism (or antitrinitarianism) refers to Christian belief systems that reject the doctrine of the Trinity as not having scriptural origin. Nontrinitarian views differ widely on the nature of God, Jesus, and the Holy Spirit. Various nontrinitarian views, such as Adoptionism, Monarchianism and Arianism existed prior to the formal definition of the Trinity doctrine in AD 325, 360, and 431, at the Councils of Nicaea, Constantinople, and Ephesus, respectively. Following the final victory of orthodoxy at Constantinople in 381, Arianism was driven from the Empire, retaining a foothold amongst the Teutonic tribes. When the Franks converted to Catholicism in 496, however, it gradually faded out. Nontrinitarianism was later renewed in the Gnosticism of the Cathars in the 11th through 13th centuries, in the Age of Enlightenment of the 18th century, and in some groups arising during the Second Great Awakening of the 19th century.
Modern nontrinitarian groups or denominations include Christadelphians, Christian Scientists, The Church of Jesus Christ of Latter-day Saints, Dawn Bible Students, Friends General Conference, Iglesia ni Cristo, Jehovah's Witnesses, Living Church of God, Members Church of God International, Oneness Pentecostals, the Seventh Day Church of God, Unitarian Universalist Christians, United Church of God, and The Shepherd's Chapel.
Islam considers Jesus to be a prophet, but not divine, and Allah to be absolutely indivisible (a concept known as tawhid). Several verses of the Qur'an state that the doctrine of the Trinity is blasphemous.
"Say: He is God, the One and Only; God, the Eternal, Absolute; He begetteth not, nor is He begotten; And there is none like unto Him.
The Qur'an makes several errors in its interpretation of the Christian Trinitarian doctrine. It mistakenly presupposes the Trinity to be composed of the Mother (Mary), the Son (Jesus), and the Father (Allah), replacing the Holy Spirit with Mary, making the Father the third person rather than the first, and assuming the persons to be three separate gods—a tritheism—rather than one God existing in three inseparable persons—a Trinity, or Tri-unity:
Certainly they disbelieve who say: Surely Allah is the third (person) of the three; and there is no god but the one Allah, and if they desist not from what they say, a painful chastisement shall befall those among them who disbelieve.— Qur'an, sura 5 (Al-Ma'idah), ayat 73
And when Allah will say: O Isa son of Marium! did you say to men, Take me and my mother for two gods besides Allah he will say: Glory be to Thee, it did not befit me that I should say what I had no right to (say); if I had said it, Thou wouldst indeed have known it; Thou knowest what is in my mind, and I do not know what is in Thy mind, surely Thou art the great Knower of the unseen things.— Qur'an, sura 5 (Al-Ma'idah), ayat 116
Judaism traditionally maintains a tradition of monotheism to the exclusion of the possibility of a Trinity.
- Ahura, the Zoroastrian Trinity
- Ayyavazhi Trinity
- Cult of the Holy Spirit
- Islamic view of the Trinity
- Social Trinity
- Thomas F. Torrance, contemporary theologian
- Trikaya, the three Buddha bodies
- Trinitarian Order
- Trinitarian Universalism
- Trinity Sunday, a day to celebrate the doctrine
- Trimurti in Hinduism