The mystery of the Trinity is something we believe about God, but it is also a truth about us.
Many ancient religions believed that there were many different gods: gods of war, of love, of the sea, even of particular places. The people of Israel gradually came to know that there was only one God, and that belief is also held by Muslims and by Christians. But the doctrine of the Trinity, developed in the Christian faith, tells us that the one God who made the heavens, the earth and everything in them is not one individual person, but a unity of three persons in an endless and perfect relationship with each other. And it goes further, teaching us that this God of relationship desires to draw every person on the earth into that endless and perfect relationship. That is the only reason God created us: so that we can be in relationship with God and with all God’s other creatures. Being created in the image and likeness of this relationship God, we are designed to find our true selves and our ultimate fulfilment in relationship with God and with others.
This design is set deep within us but it has been overlaid, in our contemporary Western society, by a competitive individualism that is damaging to us and corrosive of the fabric of our society. Some cultures that we might describe as primitive have kept a firmer grasp on the fundamental truth that we are designed for mutual dependence and support. One example is the African proverb that it takes a whole village to bring up a child. Another is the response of a tribal chief to a Christian missionary who, having lived with the tribe for some time, giving them instruction in the faith, announced that most of them were ready for baptism, but a few were not. The chief replied that they would wait until all could be baptised together.
There is much debate about human rights in our society, but it is usually concerned with the rights of individuals, which often seem to conflict with each other or with the common good of the whole society. The doctrine of the Trinity teaches us that human dignity is ours, not mine, and that a good society is one in which everyone acts out of love and respect for everyone else, especially the weak and vulnerable, rather than pursuing their own selfish interest.