Isaiah 6.1-8; Psalm 29; Romans 8.12-17; John 3.1-17
THE doctrine of the Trinity is the fruit of the Church’s experience of Christ and of the Holy Spirit. We come to know God by participating in his life. This is the heart of the dialogue with Nicodemus in our Gospel reading. Jesus tells him that only when we are “born again of water and the Spirit” is it possible truly to know God.
Commenting on this passage, St Thomas Aquinas writes: “Just as there is a ‘sentient life’, so there is also a ‘spiritual life’, by which man is made like God and other holy spirits; and this life enjoys a spiritual vision” (Commentary on the Gospel of St John).
It is through our participation in God — being drawn, by the Holy Spirit, into his life and love — that we come to faith in him as Trinity. As Aquinas expresses it, “It is not surprising if [Nicodemus] does not see the Kingdom of God, because no one can see it unless he receives the Holy Spirit, through whom one is reborn a son of God.”
The life of God is one of endless self-giving love. Before all eternity, the Father pours out his life on the Son and on the Spirit, and they return this flow of life to its source. This circulation of life and of love is made visible to us in the life and death of Christ. It demands a revolution in our understanding of God: “The whole purpose of Jesus’ life is to replace our human conceptions of God; not only the primitive, grotesque, but also the highest, purest, and most refined” (Romano Guardini, The Lord).
It is appropriate that Trinity Sunday falls immediately after the incarnational and paschal cycles of the liturgical year, drawing out their implications for our understanding of God. In the work of redemption, each person of the Trinity is revealed to be self-emptying love, in the manner appropriate to that person.
In being “born again” in baptism, Christians are drawn into the body of Christ — and are thus drawn into the offering of love which the Son and the Spirit make to the Father. In our epistle, Paul tells us that “when we cry ‘Abba! Father!’ it is [the] Spirit bearing witness within our spirit.” We use the same intimate and loving word with which Jesus addressed his heavenly Father.
The doctrine of the Trinity is the fruit of a Church that placed the “breaking of bread” at the centre of its life. The eucharist is the summit of the Christian life of prayer. In it, we become the life with which we are fed. “It is a common act and yet at the same time deeply and intensely personal. Through this essentially material, physical activity, there is a participation in the being of God” (Kenneth Leech, True God).
This eucharistic participation brings us to the heart of God, whose very essence is the pouring out of life. (This makes it particularly fitting that we celebrate the feast of Corpus Christi on the Thursday after Trinity Sunday.)
Because God’s life is one of self-giving love, to be drawn into his life is necessarily to be sent out in love for the world. As Kenneth Leech observes, Christians “can only remain faithful in their discipleship if their Eucharistic celebration leads them to struggle and strive to create a Eucharistic world, reflecting the image and character of the Eucharistic God”.
To struggle to create a eucharistic world — as Fr Leech showed in his wider writing, and his ministry over many decades in east London — is to work for a social order that reflects the mutuality, self-giving, and joy that are celebrated in the Church’s liturgy.
Even as it sends us out to engage in this struggle, the eucharist points us to our eternal destiny. “This circulation of life and love will not come to a halt in heaven; rather, it is there that it will reach genuine efficacy. If heaven is being in God, and if the triune God is an endless exchange among the persons of God the Father, God the Son, and God the Holy Spirit, then God will draw his perfected creation into this flow of divine life” (Hans Urs von Balthasar, The Threefold Garland: The world’s salvation in Mary’s prayer).
In the life of the Trinity, we find our origin, our salvation, and our eternal home.