The Trinity is a mystery. The problem is that when we use the word mystery we think of something that we can solve if we have enough clues and enough time. This not what is meant by the technical term of 'mystery' in Theology. Based on the Greek word 'musterion' a mystery is something which is revealed to us by God which we would never have discovered by ourselves. God reveals Himself to us as Father, Son and Holy Spirit and this is something that we would never have known about God unless He had chosen to reveal it to us. He did this because He loves us. The Sign of the Cross is a physical reminder of this.

Perhaps you can remember trying to learn how to make the sign of the cross or trying to teach somebody else how to make it. The process may at one level seem simple (or actually not to begin with) but at another level it symbolizes our understanding of God. This has been revealed to us and we are called to hand it on to the next generation. It has to be taught. No one would come up with the sign of the cross without it being taught to them and ultimately it is taught to each one of us by God Himself. That is the mystery of the Trinity: that God reveals to us how much He loves us and wants us to know Him.

And the sign of the cross is an outward sign of something that should be taking place in our own lives: that each time we make this powerful gesture of faith we are committing ourselves to a life of service in the name of the Father, and of the Son, and of the Holy Spirit. Amen.