Unlike the other major feasts of the Church the Feast of the Holy Trinity does not recall a given historical event such as the birth of Jesus on Christmas Day, His death on Good Friday, resurrection on Easter Day or the descent of the Spirit on the disciples at Pentecost, which we celebrated last Sunday.
Neither is it an ancient celebration; it wasn't until the fourteenth century that this feast gained widespread recognition and began to be kept throughout the Christian world.
Perhaps it is because of this relatively late development of Trinity Sunday that Christians have struggled to articulate what it means to say that God is 'Three in One and One in Three' - the Holy Trinity.
Yet it has been and remains one of the cornerstones of our Christian faith. So what can it reveal to us today, what makes it so important to us today that it is so worthy of celebration.
First we must go back, go back to the time of the early church when Christians began to speak of God using Trinitarian language; as they reflected on the revelation of God in Jesus and the incoming and moving of God's Spirit among them.
Although the New Testament doesn't contain explicitly the doctrine of the Trinity we can read the implied Trinitarian understanding that weaves its way through the gospels and the epistles.
In recent weeks we have heard from John's Gospel of Jesus showing the disciples the Father, of him telling the disciples - 'If you have seen me you have seen the Father', and he promises the presence of the Spirit to sustain them when he would no longer be with them in the flesh.
And again in this mornings readings; in Matthews Gospel we heard of Jesus commanding his followers to go and make disciples of all nations, baptising them in the name of the Father and of the Son of the Holy Spirit.
And also in Paul's letter to the Corinthians we hear the Benediction that we are so familiar with 'The grace of the Lord Jesus Christ, the love of God, and the communion of the Holy Spirit be with you all'.
Such language enabled the early Christians to speak about Jesus and what he had done, to speak of their own experience of God as they reflected on their lives.
Trinity spoke of the dynamic action of God in creating, redeeming and sustaining and it helped them to make sense of how God relates to his creation.
By professing that God is Three in One and One in Three they were proclaiming the mystery of God, that God is community. A community of persons in relationship, a community of persons in action - creating, redeeming and sustaining with each completely involved in the work of the other two - wholly interdependent and equal. The perfect relationship. The perfect relationship based on loving and giving.
And for me today, the Trinity speaks so powerfully of what it means to be human - what it means to be made in the image of God - to be in community, in relationship.
It was John Donne who said that, 'no man is an island, complete on his own'. We have a need to be in community, to be nurtured and nourished by loving relationships. Even though we are not very good at them we need them, however complex they may be.
Our relationships come in many forms - within our families, with our friends in whose company we delight. We are in relationship with the people with whom we share the ups and downs of our day to day lives, sharing our joys and our sorrows.
It is when we come alongside and cherish those around us, when we know the security of their love and acceptance that we grow in our humanity.
For me, it is as I journey through life in the ordinary and extraordinariness of life that occasionally and wonderfully the mystery of the love of the Triune God in whose image I am made is revealed - times when I am given a glimpse of the divine, of that perfect relationship to which I feel so drawn to.
But there is more - it is about more than us and those we have personal contact with. When we reflect on the threefold action of God in our world today - creator, redeemer and sustainer we are called to reflect on our capacity to be creative, to work for the good of others, to reach out to our neighbours farther afield, to our brothers and sisters around the world, especially to parts of our world where there is destruction and despair. To reach out with projects such as and our forthcoming Vine Trust project here at All Saints. An initiative that has grown our of community - our Lent Reading Group - and our desire to reach out in prayer and action to another community - and to be in relationship with other much farther afield. Surely by responding to calls such as these and by professing our faith in that relationship of Trinity that we acknowledge our desire to be drawn ever deeper into that community of love that is God and in so doing we can become more fully the people we are called to be.
Julian of Norwich, saint and mystic of the fourteenth century wrote this short but profound exchange - "Would you know your Lord's meaning?" she asks. "Know it well, love was his meaning. Who showed it to you? Love. What did he show you? Love. Why did he show it? For love."
It all comes back to love and relationship - the transforming and healing love exemplified in the Divine relationship of the Father, the Son and the Holy Spirit, in whom we are about to stand and profess our faith as we do each Eucharist. Most certainly worth giving thanks for and celebrating today - Trinity Sunday.
Amen.
Sermon by: Christine Barclay