VATICAN CITY (CNS) — Noting that “realities are more important than ideas,” Pope Francis told a group of ecumenists that they “must be oriented to addressing the real concerns” of churches worldwide.

The pope issued the call in a message marking the 50th anniversary of the Joint Working Group of the Catholic Church and the World Council of Churches.

Cardinal Kurt Koch, president of the Pontifical Council for Promoting Christian Unity, read the message to the group, gathered for a conference June 23 in Rome.

The anniversary serves as a “moment to thank the Lord for all the ecumenical movement has achieved,” the pope said in his letter, addressed to WCC General Secretary Olav Fykse Tveit.

The nine reports produced by the Joint Working Group in the past 50 years, the pope wrote, “witness to the growing understanding and appreciation of the bonds of brotherhood and reconciliation” among Christians, which sustain them in their “common witness and evangelizing mission” in “the changing landscape of Christianity in the modern world.”

However, the pope also warned the group from being “an inward-looking forum.”

“Rather, it must become ever more a think tank, open to all the opportunities and challenges facing the churches today,” as they accompany “suffering humanity on the path to the kingdom, by imbuing society and culture with Gospel truths and values,” he wrote.

Referring to the “scandal of division between Christians,” the pope encouraged the group to continue dialogue and to “promote ways for Christians to testify together to the real, though imperfect, communion shared by all the baptized.”