They were both convinced that the reunion of Christendom — though divinely willed — would not be attained without fervent and sustained prayer. The Church Unity Octave, now the Week of Prayer for Christian Unity, this year celebrated Jan. 18-25, was observed for the first time in 1908 at the friars’ and sisters’ motherhouse chapel at Graymoor in Garrison, N.Y.

A century later, looking at the ongoing elusiveness of the goal of unity among the followers of Jesus, we might be tempted to say with a heavy heart, like the two disciples on the road to Emmaus: “We had hoped” (Lk 24:21). But that, I believe, would be a sin against the Holy Spirit.

Let’s be clear: only the Holy Spirit has the power to heal the divisions within the church of Christ. The Council Fathers at Vatican II said it without ambiguity in the Decree on Ecumenism:

“It is the Holy Spirit, dwelling in those who believe and pervading and ruling over the entire church, who brings about that wonderful communion of the faithful and joins them together so intimately in Christ that He is the principle of the church’s unity (no. 2).

“Further, this council declares that it realizes that this holy objective — the reconciliation of all Christians in the unity of the one and only church of Christ — transcends human powers and gifts” (no. 24).

But while the Holy Spirit is the creator, the originator of the movement for union, we are the collaborators. And as in all other things, God does not impose unity upon us, but invites our willing co-operation.

The American Methodist theologian Albert Outler was an official observer at Vatican II. The words he addressed to leaders of religious communities in the Catholic Church need to be heard again today. He challenged them and the members of their communities to take up the ecumenical cause once more and make it their own, “not because you are vowed to unity more than other Christians, but because you are vowed to holiness.”

“My plea,” said Outler, “is that in your zeal for God’s reign you should never ease the cause of Christian unity over the margins of your commitments, never rank it as a deferred priority, never rest content with the ecumenical status quo, which is still a scandal — in God’s eyes and even in the eyes of the world.”

One of the examples in early ecumenical leadership that stay with me is that of the former World Council of Churches general secretary, Eugene Carson Blake. He was a man much on the move, but he set aside one full day for prayer each week in the midst of his many travels and demanding schedule. Prayer is the way we give God’s Spirit the room to move where the Spirit wants to move.

A powerful reason for making prayer for unity a top priority once again is that prayer’s first effect is in us. When we pray sincerely and honestly, we dispose ourselves to accept and to act in accordance with God’s will. Prayer changes hearts, and it is essentially hearts that need to be changed.

The Week of Prayer for Christian Unity is not simply a moment in the year to make visible our convictions about church unity. It is, most fundamentally, an occasion when we express our belief in the power of prayer to change hearts.

In the intimacy of prayer, we experience the God who loves all the members of the different churches. In prayer we enter into a deeper solidarity with them, recognizing that they are members of the same Lord: “There is one Lord, one faith, one baptism.”

The Second Vatican Council identified “change of heart and holiness of life,” along with prayer for unity, as the soul of the ecumenical movement. Without this foundation, all unity initiatives would be in vain. Prayer is the hinge on which an ecumenically minded Christian’s effectiveness and staying power rests.

In one of his addresses to the members of the Vatican curia, Pope John Paul II told them, “I pray every day for unity among Christians.” How different the church of Christ would appear before the world today if members of all our churches could say the same.

If you’re looking for a daily prayer that says a lot concisely, here is one of my favourites, composed by the Faith and Order Commission of the World Council of Churches:

O God, holy and eternal Trinity,
we pray for your church in the world.
Sanctify its life; renew its worship;
empower its witness; heal its divisions;
make visible its unity.

Lead us, with all our brothers and sisters,
towards communion in faith, life, and witness,
so that, united in one body by the one Spirit,
we may together witness to the perfect unity
of your love.

(Fr. Ryan directs the Paulist North American Office for Ecumenical and Interfaith Relations in Washington, DC.)