ROME (CNS) — Christians must work together to offer the faith they share to a world that seems to find it more and more difficult to believe, Pope Benedict XVI told Catholic, Orthodox, Anglican and Protestant leaders.

“Unity is in itself a privileged means — almost a requirement — for proclaiming the faith in an increasingly credible way to those who do not yet know the Savior or who, having received the proclamation of the Gospel, have almost forgotten this precious gift,” Pope Benedict said Jan. 25.

Presiding over an evening prayer service at the end of the Week of Prayer for Christian Unity, the pope said that, even as divided Christians continue their theological dialogues in the search for full unity, “It is necessary to pursue concrete collaboration among the disciples of Christ on behalf of the cause of transmitting the faith to the modern world. “

In today’s society, it seems that the Christian message has a diminishing impact on personal and community life, and this represents a challenge for all churches and ecclesial communities,” Pope Benedict said in his homily at Rome’s Basilica of St. Paul Outside the Walls. The key to meeting the challenge, the pope said, is for Christians to pray to God for the gift of unity and step up their efforts at “reconciliation, dialogue and mutual understanding. Communion in the same faith is the basis for ecumenism,” he said.