The role of the Trinity in both liturgical prayer and mystical prayer, as different as these prayer forms might seem, must be understood within the economy of salvation, that is, in God's action to reconcile the world to himself. This involves a trinitarian dynamic, which one might call the “grammar of Christian life.” Christians are reconciled to the Father through Christ in the power of the Spirit. The relationship of Christ to the Father and to the Spirit is strikingly evident in his baptism and in his death, where his orientation to the Father and the reception and gift of the Spirit occur in what can only be called a trinitarian tableau at the beginning and end of his life. This chapter examines how the larger pattern of all liturgical action incorporates this trinitarian pattern, as do the individual sacramental rites and a number of examples of mystical prayer. That mysticism should reflect this dynamic is not surprising since the spirituality of the mystics is formed by their immersion in scripture and the liturgical life of the church.