Pope Francis said on Friday that the “barbarity of war” should inspire a new push for Christian unity.

The pope made the comment in an address to members of the Pontifical Council for Promoting Christian Unity on May 6, the 72nd day of the Russia-Ukraine war.

The conflict between the two predominantly Orthodox Christian nations has tested relations between the Vatican and the Russian Orthodox Church, as well as within Eastern Orthodoxy.

In his speech, Pope Francis said that Christian communities needed to recognize they were on a journey of faith together with the members of other confessions.

When a community tried to go it alone, he said, it ran the risk of “self-sufficiency and self-referentiality, which are grave obstacles to ecumenism.”

“And we see it,” he commented. “In some countries, there are certain egocentric revivals — so to speak — of some Christian communities that are a turning back and unable to advance. Today, either we all walk together or we cannot walk. This awareness is a truth and a grace of God.”

The pope noted that he had often described 21st-century conflicts as “a piecemeal World War III.”

“However, this war, as cruel and senseless as any war, has a greater dimension and threatens the entire world, and cannot fail to challenge the conscience of every Christian and every Church,” he said.

Quoting from his 2020 encyclical Fratelli tutti, the pontiff went on: “We must ask ourselves: what have the Churches done and what can they do to contribute to the ‘development of a global community of fraternity based on the practice of social friendship on the part of peoples and nations’? It’s a question we need to think about together.”

The pope suggested that efforts to improve relations between Christians in the 20th century were motivated partly by the horror of two world wars.

“Today, in the face of the barbarity of war, this longing for unity must be nourished anew,” he commented.

“To ignore divisions among Christians, whether out of habit or out of resignation, is to tolerate that pollution of hearts which makes fertile ground for conflicts.”

“The proclamation of the gospel of peace, that gospel which disarms hearts even before armies, will be more credible only if proclaimed by Christians finally reconciled in Jesus, Prince of Peace.”

Members of the Pontifical Council for Promoting Christian Unity were in Rome to attend a May 3-6 plenary meeting on the theme “Towards an Ecumenical Celebration of the 1,700th Anniversary of Nicaea I (325-2025).”

Among the speakers was Major Archbishop Sviatoslav Shevchuk, the head of the Ukrainian Greek Catholic Church, who addressed plenary participants remotely about the ecumenical situation in Ukraine amid the war.

In his speech, the pope said that members of the pontifical council were making a “valuable contribution” by reflecting on how to celebrate the anniversary of the First Council of Nicaea “in an ecumenical manner” in 2025.

The council, held in 325 A.D., was called by the emperor Constantine to confront the Arian heresy, which denied Christ’s divinity. The council promulgated the Nicene Creed, which is still accepted by Orthodox, Anglican, and other Protestant denominations.

“Despite the troubled events of its preparation and especially of the subsequent long period of reception, the first ecumenical council was an event of reconciliation for the Church, which in a synodal way reaffirmed its unity around the profession of its faith,” the pope said.

“The style and decisions of the Council of Nicaea must enlighten the present ecumenical journey and lead to new concrete steps towards the goal of fully restoring Christian unity.”

“Since the 1,700th anniversary of the First Council of Nicea coincides with the Jubilee year, I hope that the celebration of the next Jubilee will have a significant ecumenical dimension.”

The Pontifical Council for Promoting Christian Unity, led by the Swiss Cardinal Kurt Koch, traces its roots back to 1960, when Pope John XXIII established the Secretariat for Promoting Christian Unity. It was given its current title by Pope John Paul II in 1988.

The pontifical council — located on the Via della Conciliazione, the road leading from St. Peter’s Square to the Castel Sant’Angelo — will be renamed the Dicastery for Promoting Christian Unity when the new Vatican constitution comes into force on June 5.