Today is Trinity Sunday, the day when we particularly remember that God is three-in-one: God the Father, God the Son and God the Holy Spirit. Unusually, among the special occasions that we celebrate each year, it’s not based on a particular event: Christmas, we celebrate Jesus birth, Good Friday the death of Jesus on the Cross, Easter Sunday his resurrection, and last Sunday, Pentecost, we celebrated the coming of the Holy Spirit. But Trinity Sunday doesn’t remember a particular event or occasion. Instead, today we remember a doctrine of the church, a theological concept. God is God. And God is God the Father. And God is God the Son. And God is God the Holy Spirit. The word ‘trinity’ doesn’t appear in the bible - rather the doctrine of the trinity was developed over time to explain how we encounter God in our scriptures. That we see God the Father, God the Son and God the Holy Spirit – but yet we see that there is one God. And while we don’t read the word ‘trinity’ in the scriptures, we do see the persons of the trinity, present and distinct. The most famous of these is probably the baptism of Jesus, where God the Son is baptised, God the Father speaks from heaven (“You are my son, the beloved”) and God the Holy Spirit descends on Jesus. And another famous one is the great commission, which is one of today’s readings, where Jesus commissions the disciples to baptise people in the name of the Father, and of the Son, and of the Holy Spirit. But while the concept of the trinity is important to our theology (our understanding of God, we aren’t made right with God because we have a sound grasp of the doctrine of the trinity, we are made right with God only because of our faith in Jesus, who died for us. In the traditional creeds of the church, including the Nicene Creed, which is part of today’s service, we state what we believe as Christians: ‘We believe in one God, the Father, the Almighty…We believe in one Lord, Jesus Christ, the only Son of God…We believe in the Holy Spirit, the Lord, the giver of life, who proceeds from the Father and the Son. With the Father and the Son he is worshiped and glorified.’ And that is the doctrine of the trinity, in a practical sense. God the creator, God the redeemer and God the sustainer. Father, Son and Holy Spirit. One God.