Introduction

This passage from the teaching of the ^{Catechism of the Catholic Church} (CCC) (234) on the profession of faith identifies the core principles and underlying recognition of Catholics regarding belief in a triune God - one God existent in three Persons: Father, Son and Holy Spirit. In addressing the people of Ephesus, St. Ignatius of Antioch (also known as Theophorus) said, faithful Christians were ‘being stones of the temple of the Father, prepared for the building of God the Father, and drawn up on high by the instrument of Jesus Christ, which is the cross, making use of the Holy Spirit as a rope, while your faith was the means by which you ascended, and your love the way which led up to God.’ (^{Ignatius of Antioch, 2014}, loc. 4027.) St. Ignatius goes on to say, ‘the Holy Spirit does not speak His own things, but those of Christ, and that not from himself, but from the Lord’. The point St. Ignatius was making is that the three Persons of the triune God are integrally connected, and it is through the grace of the three-in-One that salvation is gained. Hence, the Trinity is the core of the Christian faith, but from the very beginning the faithful relied on metaphor to explain and help others understand how Three could be One. Additio- nally, the three Persons are not to be understood as merely three aspects or personalities of God. Nor are they to be understood as three separate individuals comprising some sort of collective or union of gods. Rather, the mystery of the Most Holy Trinity is how to understand how a single, unified, undifferentiated God (Dt. 6:4) can be understood as both one God and three Persons (^{Augustine, 2013}, loc. 24470). As Pope Paul VI made clear (in Mysterium Filii Dei, 1972), the Most Holy Trinity is not an evolutionary development of God arising out of the incarnation of Jesus Christ, but rather it is through Christ’s incarnation that the trinity of God has been revealed (as cited in ^{Neuner & Dupuis, 2001}, p. 158). From the very beginning of the Old Testament God is referred to in the plural (Gn. 1:26); throughout the Old Testament prophets identify receiving God’s grace and support through the Spirit (Ex. 31:3; Nb. 11:17 & 25-29; Jg. 6:34 & 13:25; 1S 10:6 & 16:13) or God’s revelation and wisdom by way of God’s Spirit (Ezk. 11: 5; Mi. 3: 8; Ze. 7: 12), which St. Paul identifies as the Holy Spirit (Ac. 28:25); and in the New Testament the full recognition of the unity and singularity of the Trinity is declared to have been revealed (Jn. 1:1; Ac. 4:24-25). As stated, metaphor is a powerful method of teaching about God, especially with regards to the Trinity, and this can be seen in the book of Genesis when it says, ‘Yahweh God shaped man from the soil of the ground and blew the breath of life into his nostrils, and man became a living being.’ (2:7) Thus, in terms of metaphor God the Father can be seen in His creative power, God the Holy Spirit can be seen in life giving breath, and God the Son can be seen in the epitome of the lived example of man as Christ Jesus (cf. Dei Verbum, 3-4, as cited in ^{Flannery, 1992}; hereafter simply cited as DV). As a teaching, therefore, understanding the mystery of the Most Holy Trinity opens Scripture to more than an historical account of people and their beliefs, and sheds light onto the mystery of creation, the nature of God, and meaning of life.

In developing an understanding of the mystery of the Most Holy Trinity, it is important to clarify the fundamental aspects of each part of the theological concept contained therein. Therefore, in understanding the teaching of the mystery of the Most Holy Trinity as the central mystery of Christian faith and life, and as the source of all other mysteries of faith and which illuminates their meaning and significance, the concept of mysteries of faith will be explained. Subsequently, a clarification of the forms of revelation by which mysteries are made known and understood will be provided. This will be followed by an exposition of what is meant by the mystery of the Most Holy Trinity, as well as two subsequent sections on the impact and implications of this mystery on Christian life.

Mysteries of faith

A ‘mystery of faith’ is more than simply something that is unknown or incomprehensible. Rather, mysteries of faith refer to those things that cannot be know through human reason alone; they are dependent on divine revelation. Scientifically, speculation can be made as to how the universe came into being or how life originated and developed (or evolved), these are things that can be approached and possibly understood through human reason. The ancient philosopher Aristotle (2016) identified four causes of things: material, formal, efficient and final. Thus, science may attempt to address the material cause (i.e., what a thing is made of ) and the formal cause (i.e., how a thing is designed or organised), but it does not adequately account for the efficient cause (i.e., the originating movement or force bringing about creation) nor the final cause (i.e., the ultimate purpose for bringing the thing into existence). In other words, the ‘Big Bang’ may seek to explain the origin of the universe, but it says nothing about the originating movement that caused the quantum singularity to expand in the first place. Similarly, evolution may be used to describe how species have developed and changed to fit their environments, but it says nothing about the ultimate purpose of life beyond simply procreating to keep the process going (cf. ^{Pius XII, 1950}). Hence, by reason alone we cannot know or fully understand creation or existence because the efficient and final cause of things remains a mystery. To grasp the metaphysical understanding of such things (i.e., the underlying reality that supports physical existence) - knowledge that exceeds human ability - revelation is required. Such revelation can only come from that which is outside of creation, beyond the materiality of existence; otherwise the infinite regress of causation would lead to a truncation or paralysis of thought. In terms of human discussion and speculation, the only candidate for an essence outside of creation is God. In ancient philosophy, the essence or force which moved all other things (e.g., the quantum singularity of the Big Bang) was described ambiguously as the unmoved mover (^{Aristotle, 2016}, book 9; although Plato did assert the idea of a divine creator, referred to as a “demiurge”, which was responsible for creation, cf. ^{Plato, 2008}), but in Christianity this creative force is recognised as the triune God. St. Thomas Aquinas states, ‘God is the First Mover, and is Himself unmoved (^{Aquinas, 2010}, loc. 799). As such, belief in God precedes human understanding of metaphysical truths, and faith in the veracity of God is required to accept and assent to those truths as revealed by God (^{Aquinas, 2010}, loc. 513; also cf. 2Co. 10:4). Mysteries of faith, therefore, are the truths revealed by God (DV, 5). Consequently, before examining what constitutes a mystery of faith (particularly the mystery of the Most Holy Trinity), it is important to first take a moment to clarify forms of revelation by which the mysteries of faith are made known.

Forms of Revelation

Revelation from God may be given in several ways, generally identified as: 1) nature/creation; 2) prophets/ prophesy; 3) Scripture; 4) tradition; and 5) ecclesial magisterium. As St. Paul writes, ‘ever since the creation of the world, the invisible existence of God and his everlasting power have been clearly seen by the mind’s understanding of created things’ (Rm. 1:20). Similarly, the Vatican II document Dei Verbum (3) points out, ‘God … provides men with constant evidence of himself in created realities’ (^{Flannery, 1992}, p. 751), such that the lessons of birth, life, death, decay and new life as seen in nature, metaphorically demonstrate God’s gifts of creation, spiritual sustenance, human separation through sin and spiritual death, and reveal the promise of Grace and reconciliation are made manifest. St. Paul makes these connections clear in discussing the importance of the apostolate and the choice each person must make in accepting or rejecting God’s revelation (2Co. 2:14-16). Thus, God’s revelation through creation is understood as a general revelation accessible to all, and for which all are held to account (Ps. 19:1-4; Jm. 4:17). Complimentarily, God’s grace of revelation directly to people (e.g., through prophets, Scripture, tradition and the magisterium), otherwise described as special revelation, help to ‘let us know the mystery of his purpose’ (Ep. 1:8). As St. Paul describes it, ‘he made known to me the mystery … as it is now revealed in the Spirit of his holy apostles and prophets’ (Ep. 3:3-5), and the mystery he describes is the working of God in the Trinity to bring about salvation to all of humanity. Showing once again that through revelation the mystery of the Most Holy Trinity is central to Christian faith and life as ‘the source of all the other mysteries of faith, the light that enlightens them’ (CCC, 234).

The Mystery of the Most Holy Trinity

The idea of mystery, that which cannot be know through human reason alone, runs throughout Christian tradition and can already be seen in the Old Testament book of Daniel (2:18-19) where he asks his friends to pray to God for revelation of divine mystery. Revelation of divine mystery is associated with bestowing wisdom upon the faithful (1Co. 2:7). ^{Immanuel Kant (1960)} argued that the mystery of the Trinity is completely beyond human reason and can only be understood in terms of morality; whereby God the Father gives the law, the Holy Spirit provides wisdom to understand the law and judgement, and Jesus the Son provides the grace of salvation through forgiveness of transgressions of the law, i.e., sin. As St. Paul states, ‘all have sinned and lack God’s glory, and all are justified by the free gift of his grace through being set free in Christ Jesus’ (Rm. 3:23-24). Kant’s position, thus, is that the mystery of the Trinity - as three Persons in One - cannot be known or understood theoretically in terms of a metaphysical comprehension; only a practical understanding of God in relation to the moral law is possible. (On the moral necessity of divine revelation, see Pope ^{Pius XII’s (1950)} encyclical Humani Genaris.) Yet, St. Paul seems to indicate the possibility of grasping more than the functioning of God in terms of the moral law, and points to the nature of God by identifying the core mystery of faith and the foundation upon which all other mysteries of faith rest in his first letter to Timothy:

Without any doubt, the mystery of our religion is very deep indeed: [Christ] was made visible in the flesh, justified in the Spirit, seen by the angels, proclaimed to the gentiles, believed in throughout the world, taken up in glory (1Ti. 3:16).

St. Paul, in identifying Christ Jesus as the mystery of the Christian faith, is signifying that through the power of God the Father, with the actions of the Holy Spirit, Jesus as the Son of God is made manifest in creation and revealed as the totality of a triune God in the form of the Most Holy Trinity. As the mystery, understanding the Trinity is key to addressing all other mysteries of faith and the corner-stone for all catechetical teaching. Nothing exists except through God the Father (Jn. 1:3), nothing is understood except through God the Holy Spirit (Is. 11:2), and nothing is redeemed except through Jesus Christ as the Son of God (Jn. 14:6).

To clarify this even further, it is important to unders- tand the Greek word μυστήριον (musterion), which is translated into English as mystery (^{Harvey, 1980}). However, in religious terms, μυστήριον is generally understood not simply as something unknown but rather as something sacred that is unknown to the uninitiated. It is for this reason that μυστήριον was frequently translated into English, based on Pauline theology, as sacrament (^{Stout, 2014}). Thus, the mysteries of faith are often understood as the sacraments of the Catholic faith: Baptism, Reconciliation, Eucharist, Confirmation, Marriage, Holy Orders, and Anointing of the Sick. All of these mysteries (sacraments) reveal the grace and salvation of God, by the working of the Holy Spirit, as brought to completion through the life, death and resurrection of Jesus Christ. St. Ambrose identifies the mysteries of faith running throughout the Old Testament and into the New Testament, culminating in the death and resurrection of Jesus Christ, as foreshadowing salvation: the significance of the sacrament of baptism anticipated in the stories of Noah, Jonah and Moses, and leading to the mystery of the virgin birth as an act of God’s grace for the reconciliation of humanity, which reaches its fulfilment in the cross of Jesus Christ (Ambrose, 2014). St. Paul associates the re- velation of Jesus Christ as fundamental to the mystery of God (Rm. 16:25) and, as such, the Most Holy Trinity is the basis for all other mysteries, ‘the light that enlightens them’ (CCC, 234).

Impact of the Mystery of the Most Holy Trinity on Christian Faith

Recognition of God in three Persons does more than simply provide a variety of ways to relate to God. It is not just a question of praying to God as a plurality of personalities or as if there is a division of labour within a God who wears many hats. This is the view taken by Hinduism, which asserts the One God of Brahman who is understood as comprised of the Trimurti as Brahma, Vishnu and Shiva (creator, preserver and destroyer; respectively) and is divided into avatars and prayed to in various ways for different causes, e.g., praying to God in the form of Ganesh to remove obstacles and provide a mindset conducive for worship, or praying to God in the form of Rama for protection (^{Daniélou, 1991}). Such an understanding risks anthropomorphising God and conceiving of God in a functionalistic way. As Reinhold Bernhardt (2014) says, ‘those analogies to Trinity are subordinated functions of the higher impersonal reality (Brahman), whereas the Christian understanding of Trinity is believed to be Godself (the ‘nature’ of God) as the ultimate reality’ (p. 52). The difference is that a functionalist understanding of the Trinity asserts the revelatory actions of God to be identical with the divinity of God, whereas the Christian doctrine of the Trinity asserts that what is revealed in each of the three Persons of the Trinity - Father, Son and Holy Spirit - is the nature of God. The nature of God as creator is revealed in the Personhood of the Father, the nature of God as the wisdom of creation is revealed in the Holy Spirit, the nature of God as salvific is revealed in Jesus Christ. In this way, ‘the Godhead … are related in an essential unity, but not in an undifferentiated identity’ (^{Bernhardt, 2014}, p. 58). In other words, God the Father, God the Son, and God the Holy Spirit do not refer to individual attributes of the one God, they each refer to the complete and undivided essence of God. In the book of Exodus, God identifies himself as ‘I am he who is’ (3:14), which St. Thomas Aquinas explains reveals that God’s essence is existence (^{Aquinas, 2010}, I, 13, 11:1). ^{John Macquarrie (1982)} cites St Augustine in describing the problem as a ‘poverty of language’, whereby the term ‘person’ commonly refers to a substantial being while the term essence contains no such connotation (p. 193). The confusion of essence arises when one fails to recognise the fullness of God in each Person of the Trinity and sees God as a composite of the three (^{Augustine, 2013}, ch. 9). The problem for Christians is not being able to recognise the fullness of God in the person of Jesus Christ, as St. Thomas Aquinas says, ‘for although it was wholly united to the human nature in the one Person of the Son, yet the whole power of the Godhead was not circumscribed by the human nature’ (^{Aquinas, 2010}, III, 10, 1:2). Bernhardt points out, ‘the self-communication of God is concentrated in Jesus Christ but not confined to him’ (^{Bernhardt, 2014}, p. 61). Therefore, the mystery of the Most Holy Trinity is a difficult concept to grasp, but once understood as the fullness and essence of God as revealed in the three Persons of Father, Son and Holy Spirit, it brings to light all mysteries that had been previously revealed yet not fully understood.

The impact of the mystery of the Most Holy Trinity for the Christian faith, therefore, is that it provides an opportunity unavailable in alternative conceptions of God. The Jewish tradition has access to the revelation of God through the books accumulated in the Old Testament. As has already been stated, the essence of God revealed in the Trinity is already present in the Scriptures and the teachings of the prophets, but it only becomes explicitly articulated in the revelation of Jesus Christ. In other words, Jesus Christ makes the promise of God - a promise that has been renewed over and over again through covenant after covenant in the Jewish faith - immediately present in the here and now. The ^{Catechism of the Catholic Church} makes clear that the fullness of God is present in Jesus Christ (547), responding to Christ Jesus is an acceptance of God’s promise (548), a promise not made by compulsion but by invitation (549), it is the promise of a reconciled and fulfilling relationship with the creating God that gives all things life and reveals the mysteries of the universe (550). And, it is through the wisdom of the Holy Spirit that these mysteries are understood (CCC, 692). Speaking of his physical departure to his disciples, Jesus Christ emphasised the continuing presence of God in the form of the Holy Spirit by saying, ‘when the Spirit of truth comes he will lead you to the complete truth’ (Jn. 16:13). This demonstrates that the three Persons of the one God, each completely God and yet each completely unique, unite to form a complete understanding of the essence of Being and the hope of creation.

Understanding the mystery of the Most Holy Trinity allows Christians to recognise the dynamic interrelation-ship of the triune God and discover for themselves the opportunity for salvation - salvation from the separation of themselves from the very source of creation and all that is, and their separation from understand their ultimate purpose in life, i.e., the efficient and final causes of all things (Rm. 8:1-30). Yet, this knowledge brings with it implications for Christian life. As it is written in the epistle of James, ‘everyone who knows what is the right thing to do and does not do it commits a sin’ (4:17). And, as written in the book of Proverbs, ‘Yahweh’s eyes protect knowledge, but he confounds deceitful speeches’ (22:12). Therefore, it is important to examine the implications for Christian life of understanding the mystery of the Most Holy Trinity.

Implications of the Mystery of the Most Holy Trinity for Christian Life

In St. Paul’s second letter to the Thessalonians, he states,

‘God chose you from the beginning to be saved by the Spirit who makes us holy and by faith in the truth. Through our gospel he called you to this so that you should claim as your own the glory of our Lord Jesus Christ. Stand firm, then, brothers, and keep the traditions that we taught you, whether by word of mouth or by letter. (2Th. 2:13-15)’

In this passage, St. Paul identifies that Christians are called to model their lives around the lived example of Jesus Christ and to live by the teachings of God through the Holy Spirit. He also indicates the five forms of revelation previously mentioned (see the previous section on forms of revelation), referring to: 1) nature/creation by saying God chose people from the beginning; 2) prophets/prophesy by saying that those chosen live by faith in the truth; 3) Scripture by referencing the gospels that have been given; 4) tradition by making clear that the ways Christians ought to live have already been taught; and 5) ecclesial magisterium by referencing the teachings through the disciples as given through direct communication, orally and in writing. Hence, the implications of the mystery of the Most Holy Trinity for Christian life is the call to hear and respond to the truth of God. To clarify this further, and to contextualise this understanding within this course as preparation to be a catechist and a permanent deacon, the implications of the Trinitarian mystery will be examined, first, generally for all Christians; second, particularly for catechists; and, third, specifically for permanent deacons.

First, St. Paul in his letter to the Colossians said, ‘we have never failed to remember you in our prayers and ask that through perfect wisdom and spiritual understanding you should reach the fullest knowledge of his will and so be able to lead a life worthy of the Lord’ (1:9-10). The grace of understanding the mystery of the Most Holy Trinity is not solely a revelation of the essence of God, it also reveals the purpose of creation and establishes a vocation to share God’s love through ‘every kind of good work’ and to grow ‘in knowledge of God’ (Col. 1:10). Thus, understanding and accepting the revelation of the mystery of the Trinity calls the faithful further ‘to be holy - not because of anything we ourselves had done but for his own purpose and by his own grace’ (2Ti. 1:9). Therefore, the implications of the mystery of the Most Holy Trinity for the apostolate of Christian life is that all are called to serve God and strive to know God more fully.

Second, catechesis is the act of teaching others in the faith and truth of God (CCC, 4). As such, catechists are called to introduce, clarify and instruct on the mysteries of the faith. As has been articulated above, the mystery of the Most Holy Trinity is key to understanding all other mysteries of faith because it is the basis for coming to comprehend and know the essence of God. Hence, catechesis ‘concerns the very foundations of human and Christian life; for it makes explicit the response of the Christian faith to the basic question[s]’ of creation, questions which are ‘decisive for the meaning and orientation of our life and actions’ (CCC, 282). The implications of this for the life of a catechist is to recognise, as St. Paul stated above, that everyone has already been called to enter into a relationship with God and the catechist is called to provide the clarity of the mystery of the Trinity to allow those relationships to flourish and bear fruit (CCC, 2688). The letter to the Hebrews exhorts us to ‘leave behind us then all the elementary teaching about Christ and go on to its completion’ (Heb. 6:1). The completion being the understanding of the fullness and essence of God in the Most Holy Trinity, and the acceptance of the call to respond to live in communion with God. As Pope ^{John Paul II (1979)} stated, ‘Catechesis is intimately bound up with the whole of the Church’s life’ (para. 13). Consequently, the implication for the apostolate of catechists is that teaching the mystery of the Most Holy Trinity is nothing short of teaching the message of salvation to all people and sustaining the life of the Church.

Third, in his first letter to Timothy, St. Paul explains that ‘deacons must be respectable’ and ‘they must hold to the mystery of the faith with a clear conscience’ (1Ti. 3:8-9). This provides a clear direction that anyone called to the permanent diaconate must hold fast to the grace and wisdom of God granted through revelation and remain faithful to the mystery revealed in the Most Holy Trinity. St. Luke in recording the Acts of the apostles describes deacons as being ‘filled with the Spirit and with wisdom’ (6:3). As stated previously, the Spirit is the full essence of God through which grace imparts wisdom to the faithful; wisdom of the laws and wisdom in living in accordance with the will of God. Permanent deacons, therefore, must base their lives on the mystery of the Most Holy Trinity and work to draw others to the love of God. The ^{Catechism of the Catholic Church}, clearly state that permanent deacons have a specific catechetical role in sharing Christ’s mission to serve the people of God, especially in teaching and sharing the mysteries of faith in the form of the sacraments (CCC, 1570). As previously noted, the sacraments are the mysteries of faith, i.e., the revealed truths of God (DV, 5), and it is the permanent deacon’s role to teach the full meaning and significance of these truths. Therefore, the implications of the mystery of the Most Holy Trinity for the apostolate of permanent deacons is that it establishes their call to participate in the mission of Jesus Christ by teaching how each of the mysteries of faith (i.e. sacraments) reflect the essence and fullness of God.

Conclusion

The aim of this article has been to explain how the mystery of the Most Holy Trinity is the central mystery of Christian faith and life, and how understanding this mystery clarifies and illuminates all other mysteries of the Christian faith. In doing this, the fundamental aspects of each part of the theological concept of the Trinity have been elucidated and contextualised within Christian doctrine, tradition and teaching. By explaining what is meant by ‘mystery of faith’, it has been shown that human reason alone is insufficient for fully comprehending the metaphysical truths of creation and is integrally dependant on divine revelation. The various ways in which the ultimate truths of reality are revealed were discussed and shown to illuminate the nature of God as a Trinity through the workings of God. The triune nature of God as three Persons in one was explained as the essence of God and further clarification of the meaning of mystery was given to identify how mysteries of faith - as understood as sacraments - each illustrate the salvific grace of God, which can only be fully understood through the mystery of the Most Holy Trinity. Finally, the impact of understanding the mystery of the Most Holy Trinity on Christian faith was discussed, and the implications of this understanding for the apostolates of all Christians in general, catechists in particular, and permanent deacons specifically was explicated. What this has all demonstrated is the critical importance for all Christians to seek to understand the mystery of the Most Holy Trinity as the key to coming to a fuller knowledge of God as the basis, meaning and purpose of life.