The Sunday after Pentecost bears the designation Trinity Sunday. It is the only day in the liturgical calendar that expressly reflects on God’s self-revelation as the Triune One. While the doctrine of the Trinity is not summarized succinctly in Scripture (but as any doctrine, really?), the narrative of God’s history with humanity is surely trinitarian. As Alister McGrath puts it, “God plays all the roles” in the divine work of creation and redemption. The act of creation itself bespeaks God’s triune identity: word and breath evoke beginnings. Breath sustains word, and word makes breath intelligible. “Let there be” is, thus, a complex triune utterance. Simply put, the Trinity looms in outline in the Old Testament as a mystery ready for disclosure. As long as the self-communication of God in Jesus Christ and in the Spirit had not yet occurred in a historically unrepeatable way, the full revelation of Trinity was lacking.
It is understandable that Trinity Sunday would follow Pentecost in the lectionary cycle because the doctrine of the Trinity was not fully articulated until our Christian forebears affirmed the Spirit as fully personal and fully divine. It is not surprising that the texts for this Sunday: accent God’s threefold glory (Isa. 6:3); portray God’s voice blowing through of all creation (Psalm 29); demonstrate the way the Spirit makes us present to God and to ourselves (Romans 8:12-17); and urge being born of the Spirit (John 3:5-6).
Many congregations in our day are discovering the richness of trinitarian theology as a practical doctrine that powerfully guides our life together. [I am on a mission to reform Baptists from being “sub-trinitarian.”] The trinitarian virtues of diversity, hospitality, and self-giving transform our worship, our service, and our identity as persons formed in community. Above all, the Trinity is the story of God’s yearning to be with us, drawing us into the richness of God’s life as “partakers of the divine nature” (2 Peter 1:4). This gives our lives their fullest dignity and makes clear how God intends us to live, as imago trinitatis.
Molly T. Marshall