By Richard Clifford, S.J.

We Christians define our God as the Trinity, which in traditional theological language means one God existing in three persons and one substance, Father, Son, and Holy Spirit. To arrive at this technical definition took four centuries of fierce debate by councils of the Church, especially Nicaea (325) and Constantinople (381), and by the greatest minds of those centuries. To expect ordinary Christians to understand this doctrine is asking too much. Are we then to simply accept the doctrine as a mystery that cannot be understood? Certainly not! The traditional definition and others like it were largely articulated to safeguard the official doctrine from misunderstanding.

Christians’ experience of the triune God revealed in Scripture, liturgical worship, personal prayer, and daily experience is a much different enterprise. Scripture, liturgy, and prayer bring us into the life-giving presence of the Triune God who reveals Godself to us.

The Old Testament tells us how different from its neighbors Israel’s view of God was. “Hear, O Israel! The Lord is our God, the Lord alone!” Ancient Near Eastern peoples believed in divine causality; the gods existed and acted in human affairs. In fact, they believed in multiple gods, some benign, others malign. If you got sick, a hostile god was responsible; if you recovered, a benign god was behind it. But, uniquely among its neighbors, Israel believed there was only one God, Yahweh, whom out of reverence they customarily addressed as “Lord.” Their profession of faith is summed up in an early text: “Who is like you among the gods, O Lord  / Who is like you, magnificent among the holy ones?” (Exod 15:11).

Jesus in the New Testament deepens our understanding of God. People saw him exercising the same power as Israel’s Lord in the Old Testament — calming storms, controlling the waters, and healing the sick. Their experience led them to confess in awe, “What sort of man is this, that even the winds and the sea obey him?” (Matt 8:27). What nailed it for his followers was the resurrection when he defeated the ultimate enemy death. When Jesus ascended to heaven around 30 C.E., his early followers already were giving him divine honor; there seems to have been no controversy about the practice. The early Christians remembered Jesus’s promise, especially in John 14-17, to remain with them in the Holy Spirit, the Advocate, he promised to send. St. Paul articulated this promised presence of the Spirit in his letters, notably Rom 8:5, “and hope does not disappoint, because the love of God has been poured out into our hearts through the holy Spirit that has been given to us.”

Prayer brings us before our Triune God. In the prayer for Trinity Sunday of the International Commission on English in the Liturgy (ICEL), “O God, your name is veiled in mystery, yet we dare to call you Father, your Son was begotten before all ages, yet is born in time; your Holy Spirit fills the whole creation, yet is poured forth now into our hearts.”

Richard Clifford, S.J., former President of the Weston Jesuit School of Theology and Founding Dean of the Boston College Clough School of Theology and Ministry