ARIANISM. A fourth-century heresy that denied the divinity of Jesus Christ. Its author was Arius (256-336), a priest of Alexandria, who in 318 began to teach the doctrine that now bears his name. According to Arius there are not three distinct persons in God, co-eternal and equal in all things, but only one person, the Father. The Son is only a creature, made out of nothing, like all other created beings. He may be called God but only by an extension of language, as the first and greatest person chosen to be divine intermediary in the creation and redemption of the world.

In the Arian system, the logos or word of God is not eternal. There was a time when he did not exist. He is not a son by nature, but merely by grace and adoption. God adopted him in prevision of his merits, since he might have sinned but did not. In a word, instead of being God he is a kind of demiurge who advanced in virtue and merit and thus came to be closely associated with the Father. But his nature is not of the same substance as the Father’s.

Boldly anti-Trinitarian, Arianism struck at the foundations of Christianity by reducing the Incarnation to a figure of speech. If the logos was created and not divine, God did not become man or redeem the world, and all the consequent mysteries of the faith are dissolved.

The First Council of Nicaea was convoked in 325 to meet the Arian crisis. Since the signature lists are defective, the exact number of prelates who attended the council is not known. However, at least two hundred twenty bishops, mostly from the East but also from Africa, Spain, Gaul, and Italy, signed the creed that affirmed the divinity of Christ and condemned Arius as a heretic. “We believe,” the formula read, “in one God, the Father Almighty, Creator of all things visible and invisible. And in one Lord Jesus Christ, the Son of God, the only-begotten of the Father, that is, of the substance of the Father; God from God, light from light, true God from true God; begotten, not created, consubstantial [Greek Homo ousion] with the Father.” The soul of the council was St. Athanasius (296-373), Bishop of Alexandria, whose resolute character and theological insight were the main obstacle to the triumph of Arianism in the East.

Since the fifth century, Arian churches have remained in existence in many countries, although some of them were absorbed by Islam. A principal tenet of these churches is the recognition of Christ as Messiah but denial that he is the natural Son of God.

FAITH AND REASON. The relationship between human response to God’s revelation and use of human native intelligence. This relationship is mainly of three kinds, where the role of reason is to assist divine faith: 1. reason can establish the rational grounds for belief by proving God’s existence, his authority or credibility as all-wise and trustworthy, and by proving that God actually made a revelation since he confirmed the fact by working (even now) miracles that testify to God’s having spoken to human beings, especially in the person of Jesus Christ; 2. reason can further reflect on what God has revealed and thus come to an even deeper and clearer understanding of the divine mysteries; and 3. reason can both show that the mysteries of faith are in harmony with naturally known truths and can defend their validity against the charge of being contrary to reason.

HYPOSTATIC UNION. The union of the human and divine natures in the one divine person of Christ. At the Council of Chalcedon (A.D. 451) the Church declared that the two natures of Christ are joined "in one person and one hypostasis" (Denzinger 302), where hypostasis means one substance. It was used to answer the Nestorian error of a merely accidental union of the two natures in Christ. The phrase "hypostatic union" was adopted a century later, at the fifth general council at Constantinople (A.D. 533). It is an adequate expression of Catholic doctrine about Jesus Christ that in him are two perfect natures, divine and human; that the divine person takes to himself, includes in his person a human nature; that the incarnate Son of God is an individual, complete substance; and that the union of the two natures is real (against Arius), no mere indwelling of God in a man (against Nestorius), with a rational soul (against Apollinaris), and the divinity remains unchanged (against Eutyches).

INCARNATION. The union of the divine nature of the Son of God with human nature in the person of Jesus Christ. The Son of God assumed our flesh, body, and soul, and dwelled among us like one of us in order to redeem us. His divine nature was substantially united to our human nature. Formerly the Feast of the Annunciation was called the Feast of the Incarnation. In the Eastern Churches the mystery is commemorated by a special feast on December 26. (Etym. Latin incarnatio; from in-, in + caro, flesh: incarnare, to make flesh.)

NATURE. The essence of a being considered as the principle of activity. Also the substance of a thing as distinguished from its properties, considered as the source of its operations. Nature is also definable in contrast to its opposites from a variety of viewpoints. In contrast with God, it is the created universe. In contrast with human activity, it is the world considered prior to or independent of the changes produced by human free will. In contrast to the life and operations of divine grace, it is that to which a human person has claim, as creature, as distinct from a share in God’s own life, which is the supernatural. (Etym. Latin natura, the inner principle of a thing’s operations and activity; from nasci, to be born.)

NATURAL LAW. As distinct from revealed law, it is “nothing else than the rational creature’s participation in the eternal law” (Summa Theologica, 1a, 2ae, quest. 91, art. 2). As coming from God, the natural law is what God has produced in the world of creation; as coming to human beings, it is what they know (or can know) of what God has created.

It is therefore called natural law because everyone is subject to it from birth (natio), because it contains only those duties which are derivable from human nature itself, and because, absolutely speaking, its essentials can be grasped by the unaided light of human reason.

St. Paul recognizes the existence of a natural law when he describes the moral responsibility of those ancients who did not have the benefit of Mosaic revelation. “Pagans,” he says, “ who never heard of the Law but are led by reason to do what the Law commands, may not actually ‘possess’ the Law, but they can be said to ‘be’ the Law. They can point to the substance of the Law engraved on their hearts – they can call a witness, that is, their own conscience – they have accusation and defense, that is, their own inner mental dialogue” (Romans 2:14-15).

NESTORIANISM. A fifth-century Christian heresy that held there were two distinct persons in the Incarnate Christ, one human and the other divine, as against the orthodox teaching that Christ was a divine person who assumed a human nature. Its name was taken from Nestorius (died c. 451), a native of Germanicia in Syria, and later Bishop of Constantinople. Nestorianism was condemned by the ecumenical Council of Ephesus in 431.

Postulating two separate persons in Christ, when Nestorius came to describe their union, he could not have them joined ontologically (in their being) or hypostatically (constituting one person), but only morally or psychologically. They would be united only by a perfect agreement of two wills in Christ, and by a harmonious communication of their respective activities. This harmony of wills (eudoxia) and the communion of action to which it gives rise are what forms the composite personality (henosia) of Christ.

In the Nestorian system we cannot speak of a true communication of idioms, i.e., that while the two natures of Christ are distinct the attributes of one may be predicated of the other in view of their union in the one person of Christ. Accordingly it could not be said that God was born, that he was crucified or died; Mary is not the Mother of God, except in the broad sense of giving birth to a man whose human personality was conjoined to the Word of God.

Nestorian bishops continued to propagate their views, and the confusion this produced among the people contributed to the success of Islam in the seventh century.

PUBLIC REVELATION. The supernatural manifestation of God's wisdom and will for the human race, in order to lead humanity to its heavenly destiny. It is entrusted directly to the Church for preservation and interpretation and is contained in Sacred Scripture and sacred tradition.

PRIVATE REVELATIONS. Supernatural manifestations by God of hidden truths made to private individuals for their own spiritual welfare or that of others. They differ from the public revelation contained in Scripture and tradition which is given on behalf of the whole human race and is necessary for human salvation and sanctification. Although recognized by the Church and, at times, approved by her authority, private revelations are not the object of divine faith that binds one in conscience to believe on God's authority. The assent given to them, therefore, is either on human evidence or, when formally approved by the Church, on ecclesiastical authority according to the mind of the Church. Private revelations occur as supernatural visions, words, or divine touches. Often it is impossible to distinguish the three forms in practice, especially since they may be received simultaneously.

REDEMPTION. The salvation of humanity by Jesus Christ. Literally, to redeem means to free or buy back. Humanity was held captive in that it was enslaved by sin. Since the devil overcame human beings by inducing them to sin, they were said to be in bondage to the devil. Moreover, the human race was held captive as to a debt of punishment, to the payment of which it was bound by divine justice.

On all these counts, the Passion of Christ was sufficient and superabundant satisfaction for human guilt and the consequent debt of punishment. His Passion was a kind of price or ransom that paid the cost of freeing humanity from both obligations. Christ rendered satisfaction, not by giving money, but by spending what was of the highest value. He gave himself, and therefore his Passion is called humanity's Redemption. (Etym. Latin redemptio, a buying back, ransoming, redemption.)

REVELATION. Disclosure by God of himself and his will to the human race. The disclosure comes to human beings by way of communication, which implies the communicator, who is God; the receiver, who is the human being; and a transmitter or intermediary. Depending on the intermediary, there are in general two main forms of revelation, commonly called natural and supernatural.

If the intermediary is the world of space and time, the revelation is said to be natural. In this case, the natural world of creation is the medium through which God communicates himself to humankind. Moreover, humanity's natural use of reason is the means by which it attains the knowledge that God wishes to communicate. It is therefore natural twice over, once in the objective source from which human beings derive knowledge of God and divine things, and once again in the subjective powers that a person uses to appropriate what God is revealing in the universe into which humanity has been placed. In the Old Testament those are said to be "naturally stupid" who have "not known God and who, from the things that are seen, have not been able to discover Him-who-is or, by studying the works, have failed to recognize the Artificer" (Wisdom 13:1). And St. Paul affirmed: "Ever since God created the world his everlasting power and deity – however invisible – have been there for the mind to see in the things he has made" (Romans 1:20).

Supernatural revelation begins where natural revelation ends. It is in the character of a grace from God who has decided to communicate himself in a manner that far exceeds his manifestation through nature. The Scriptures call this form of communication a divine speech and refer to God as speaking to humankind. There are two levels of this supernatural revelation, as capsulized by the author of Hebrews: "At various times in the past and in various ways, God spoke to our ancestors through the prophets; but in our own time, the last days, he has spoken to us through his Son, the Son that he has appointed to inherit everything and through whom he made everything there is. He is the radiant light of God's glory and the perfect copy of his nature" (Hebrews 1:1-2).

The difference between these two kinds of supernatural communication lies in the fact that, before Christ, God spoke indeed but still indirectly through the prophets who were inspired to tell others what Yahweh had told them. In the person of Christ, however, it was no longer God speaking merely through human seers chosen by him; it was God himself speaking as man to his fellow members of the human race. (Etym. Latin revelatio, an uncovering; revelation.)

SANCTIFICATION. Being made holy. The first sanctification takes place at baptism, by which the love of God is infused by the Holy Spirit (Romans 5:5). Newly baptized persons are holy because the Holy Trinity begins to dwell in their souls and they are pleasing to God. The second sanctification is a lifelong process in which a person already in the state of grace grows in the possession of grace and in likeness to God by faithfully corresponding with divine inspirations. The third sanctification takes place when a person enters heaven and becomes totally and irrevocably united with God in the beatific vision. (Etym. Latin sanctificare, to make holy.)

SUPERNATURAL REVELATION. Divine communication of truth in which either the manner of communication or its content is beyond the capacity of human nature to attain. Thus revelation may be supernatural in its objective source, which is more than the universe naturally tells about its Creator, and again supernatural in the subjective powers by which a person acquires what God desires to reveal. Revelation may also be supernatural in its very essence, as when God discloses such mysteries as the Trinity and the Incarnation. Or it may be, and always is, supernatural in the manner that God chooses to use for communicating himself to human beings. It partakes of a miraculous enlightenment of the seer who then serves as divine legate for sharing with others what God has supernaturally communicated to that person. In every case, however, the acceptance of revelation requires the influx of supernatural grace to enable a person to believe.

TRINITY, THE HOLY. A term used since A.D. 200 to denote the central doctrine of the Christian religion. God, who is one and unique in his infinite substance or nature, is three really distinct persons, the Father, Son, and Holy Spirit. The one and only God Is the Father, the Son, and the Holy Spirit. Yet God the Father is not God the Son, but generates the Son eternally, as the Son is eternally begotten. The Holy Spirit is neither the Father nor the Son, but a distinct person having his divine nature from the Father and the Son by eternal procession. The three divine persons are co-equal, co-eternal, and consubstantial and deserve co-equal glory and adoration.

TRINITY SUNDAY. The first Sunday after Pentecost. Its origins go back to the Arian heresy, when an office with canticle, responses, preface, and hymns was composed by the Fathers and recited on Sundays. Bishop Stephen of Liège (903-20) wrote an office of the Holy Trinity that in some places was recited on the Sunday after Pentecost, and elsewhere on the last Sunday before Advent. St. Thomas à Becket (1118-70), consecrated Archbishop of Canterbury on the Sunday following Pentecost, obtained for England the privilege of a special feast to honor the Trinity on that day. Pope John XXII (reigned 1316-34) extended the feast to the universal Church.

Modern Catholic Dictionary by Fr. John A. Hardon, S.J.