The Gospel for Trinity Sunday this year is Matthew 28: 16-20. This passage is short and familiar. It contains the risen Christ's basic commission to His apostles and through them to all Christians. They are to make disciples, baptize them in the name of the Holy Trinity, and teach them to observe Christ's teaching. All this sounds simple, but it is really quite demanding to put into practice. It is really what church history, the existence of every congregation, and the life of every Christian is about. And at the heart of it all is Baptism in the name of the Father, and of the Son and of the Holy Spirit.
Baptism in the name of the Trinity marks us as belonging to God, as members of Christ's Church, and it provides the grace to begin and continue a Christian life. Whatever our challenges or accomplishments in this life, the most important thing about us is that almighty God, the Father, and the Son, and the Holy Spirit, has claimed us as His own. He has offered us redeeming grace, and He keeps offering us renewing and sanctifying grace amidst the ups and downs of earthly life. Although theological speculations and definitions have their place, the essential importance of the doctrine of the Trinity is practical, devotional, and spiritual. It is about one God, Father, Son, and Holy Spirit, working on our souls to save us from sin and death and to offer us eternal life.