Trinity Sunday

John 16 12-15; Romans 5:1-5


May I speak in the name of the Holy Trinity, Father, Son and Holy Spirit Amen.


Today we celebrate the feast of the Trinity when we celebrate what is at the same time one of the most wonderful and puzzling aspects of the divine nature of God – that he is one God in three persons.


Interestingly, although the concept of the triune God is such a central part of our faith, the trinity is not mentioned explicitly in Scripture – the doctrine of the Trinity only became fully developed in the course of the first couple of hundred or so years that followed Jesus life, death, resurrection and ascension as theologians struggled to make sense of God’s divine intervention in the world.


Despite the fact that you won’t find specific reference to the trinity in the New Testament, the three persons of the Trinity are clearly identified throughout the gospels as for example in the passage we have just read from John’s gospel where Jesus clearly refers to both God the Father and God the Holy Spirit.


People have long struggled to find analogies to try and describe the concept of the trinity. One of the commonest analogies – reputedly first used by St Patrick is that of the shamrock leaf. Whilst helpful in some respects, we have the three leaflets which are separate and distinct but at the same time together they form the one leaf, it fails to fully express the wonder and diversity of the Trinity because each part of the leaf is just that – leaf. Apart from the slight differences in shape depending on whether it is the left hand, centre or right hand leaflet, each ‘leaflet’ is physically the same substance as the other two that make up the whole leaf.


They each have the same physical characteristics, the same colour, the same chemical composition, the same physical state – however we look at them, they are each leaf and whilst the three persons of the Trinity are one in substance, they are, as Scripture tells us and hopefully we experience,  hugely different in character.


To find an analogy that allows us greater insight into the mystery of the Trinity, I want to turn briefly to thermodynamics. Now, no need to get worried or switch off at this point for thermodynamics is all around us all the time, even if we don’t realise it, and is just the study of heat and work but as well as being absolutely fascinating and jolly useful, it can help by giving us a very useful insight into understanding the trinity.


I want us to consider for a moment one of the most abundant substances on earth – water. What we call water is the liquid form of the chemical that has the chemical formula H2O which describes a molecule comprising two atoms of hydrogen combined with a single atom of oxygen.


At atmospheric pressure H2O exists in the liquid form between 0 and +100 deg C. If we reduce the temperature below 0 deg C, thermodynamics dictates that the physical state of water changes and it solidifies and becomes what we call ice – and we had plenty of experience of that during the course of the last winter. At the other extreme, increase the temperature above 100 deg C at atmospheric pressure and thermodynamics dictates that the water boils to become what we call steam.


Chemically ice, water and steam are all H2O but physically, the three physical states are very different. One is cold and solid, useful for cooling drinks on a hot summer’s day, slippery when on a road or path and capable of splitting metal pipework apart, one is liquid, refreshing to drink, an amazingly versatile solvent, a means of transport and myriad other things beside, the third, once we had worked out how to contain, harness and control it became the source of power that powered the industrial revolution and continues to power our modern world.


Ice, water and steam are three physical forms of H2O but unlike the shamrock leaf where each leaflet is physically the same, each phase has unique and different properties. I can’t use ice to generate power in a steam turbine or steam to cool a drink on a hot summer’s day.


There is, however, one more feature that gives us an additional insight into the Holy Trinity and it is here that we need to dip a bit further into thermodynamics where we discover that there is a unique combination of temperature and pressure at which ice, water and steam can co-exist. That might seem a very strange concept and you will have to take it from me that it is true.


This point is called (pretty unimaginatively) the triple point and for water it corresponds to 0.01 deg above freezing and a pressure of about 6 mbar (6 thousandths of an atmosphere so almost a full vacuum). Under this special and unique set of conditions, ice, water and steam can co-exist. So how does that help us to understand the doctrine of the Trinity?


Well, we have the three persons of the Trinity, Father, Son and Holy Spirit, each in very nature God but each having very different characteristics – as we have just confessed in the creed – God the Father who made all things, Jesus Christ who redeemed the world and the Holy Spirit who gives life to the people of God – just as ice water and steam have very different physical properties yet the three persons of the Trinity come together uniquely and co-exist in the Godhead just as ice, water and steam co-exist at the Triple Point.


If the analogy of ice, water and steam shows us how one substance can demonstrate completely different physical characteristics and yet remain chemically unchanged and furthermore for these wildly different properties to co-exist at one point we now need to try and understand how these characteristics can be applied to people and ultimately to God as we explore the trinity further.


Before we come to the three persons of the trinity, we need to understand something about the language that we use to describe the Trinity.


When God the Father, God the Son and God the Holy Spirit are spoken of, we tend to think in terms of distinct, physical entities, three distinct, separate, people but that isn’t how theologians such as Tertullian in the third century who first started to develop and expand the concept of the Trinity understood the word we now translate as person. The modern word ‘person’ derives from the Latin ‘persona’ which wasn’t an individual person but rather described the face mask used by an actor in a play and by extension, the role or roles that they performed.


Rather than change costume or make-up, the actor would swap his face mask over as he assumed each different role. Thus one actor would adopt several different personas or characters in the course of a play, each denoted by a change of mask.


If we take that idea a bit further, we realise that it is perhaps commoner than we might imagine. We each of us exercise a number of different personas – I am the husband of my wife, the father of my children, the supervisor of the people who work for me, a direct report of my boss, a Reader in the Church of England and the list goes on.


I am the same person but in each role I inevitably adopt a different persona and demonstrate different aspects of my character. The side of my character that I demonstrate solving a complex technical problem at work is inevitably different to that which I demonstrate when bathing my three year old daughter and so we could go on.


I am not unique in this for we each one of us exhibit this multiplicity of roles or personas each of which displays a different aspect of our character and someone who only knows us in one role might be very surprised to meet us out of context.


It is hopefully as we begin to understand this idea of one person having many personas that we can begin also to understand something of the nature of the Trinity and how when we talk about the person of God we speak of a person in the modern sense but how in Father, Son and Holy Spirit we are speaking of God’s different personas.


The question can legitimately be asked why do we need the concept of the Trinity, why does God choose to reveal himself to us in the different persons of the Trinity?


The first and most obvious explanation is that God is so complex, we cannot begin to understand all that there is to know about God in a single person.


As human beings, we are incredibly complex in every sense of the world. How often do we say – I just can’t make sense of him or her. We present all sorts of different and often times confusing facets of our character to those around us.


How many of us can truly say of someone we have known for many years, say as a spouse, that they know everything about that person? The answer inevitably is none of us and so it is with God. If we can’t know everything that there is to know about a fellow human being with whom we share our lives day by day, how can we hope to know everything about Almighty God whose character is infinitely more complex than anything we can conceive however long we have known him for?


We do well at this point to reflect on the words of Augustine that ‘If you can understand it, it’s not God’. As humans we need to rationalise, explain and simplify in order to understand things that are far too complex for us to understand and we apply the same process to God. Thankfully though, God is one step ahead of us and helps us in this process through the doctrine of the Trinity for it is through the triune nature of God, Father, Son and Holy Spirit, we are helped to understand and above all, to experience personally, something of God’s wonderful love for each of us.


What we are not describing is some sort of divine, heavenly committee of three, Father, Son and Holy Spirit, one of whom draws the short straw to go to this place called ‘earth’ to visit a troublesome people in order to try and sort them out but rather three different personas of the one God revealed to through both Old and New Testaments through whom God chooses to reveal himself to us in ways that we can begin to understand and grasp.


We haven’t time this morning to explore in detail every facet of the three persons of the Trinity but in God the Father we have the God of Abraham and Israel, who chose to reveal himself to Abraham and Moses, who entered into a covenant relationship with his people Israel, who stretched out his mighty hand to rescue them from slavery, who poured out his Spirit on his people enabling them to foretell the coming of the Messiah to save his people and who ultimately raised Jesus from the grave on that glorious first Easter morning.


In Jesus, we meet with the Incarnate God, God made man who left behind the splendours of heaven to live on earth amongst us and who ultimately died on the cross for our sins only to be raised to life by God the Father and who is now ascended into heaven.


The Holy Spirit is God’s living presence with us day by day.


Paul, in the brief passage that we read from his letter to the Romans is quite explicit about the divine nature and task of the Holy Spirit when he writes “God has poured out his love into our hearts by the Holy Spirit, who he has given us”. He also reminds us how it is that because we have been justified by faith, we have peace with God through our Lord Jesus Christ, through whom we have gained access by faith into this grace in which we now stand.


Jesus tells the disciples that when the Spirit of truth, comes, he will guide them into all truth. He will not speak on his own; he will speak only what he hears – from God the Father.


Rather than being confused or mystified by the doctrine of the Trinity, we should be eternally grateful that God chooses to share so much of himself with us and at such an intimate level for given the nature of the relationship between Father and Son, Father and Spirit and Son and Spirit; as the Spirit dwells within us so we encounter both the risen Christ and God the Father in a unique and personal way.


I want to leave you with one final analogy. I want us to consider a river that flows from its source high up in the mountains down to the sea. Let’s suppose that we encounter this river as it enters the sea and we wonder from where it comes and so we set off on a journey to find its source.


As we do so, the estuary where it joins the sea, the river itself and its ultimate source are all part of the same physical entity. As we set off from the estuary where the river meets the sea to journey towards the source, it is the stream itself which guides us to its source. It shows us the way and at the same time provides us with the means of travel, guiding us and supporting us until eventually bringing us to its source.


So it is that God helps us to find him – just as the early explorers found the source of the Nile by following the Nile itself so as we seek God it is God himself who guides and directs us until such time as we encounter him for ourselves. It is the Spirit who guides us to encounter the risen Lord Jesus through whose death and resurrection we are able to be restored to fellowship with God the Father.


We have dealt with some complex theology this morning as well as some thermodynamics. If you would like to read more on the doctrine of the Trinity, I can thoroughly recommend Alister McGrath’s book Understanding the Trinity, if you want some more on thermodynamics, see me afterwards!


Above all though, may we rejoice that we can know Almighty God personally through Father, Son and Holy Spirit.  May God the Holy Trinity dwell in you richly so that you may know the wonder of God’s love for you and may evermore be defended from all adversities through Jesus Christ who is alive and reigns with you in the unity of the Holy Spirit, one God, now and for ever Amen.


Jeremy Hunns