Some 300 Christian leaders from across the denominations and traditions are in Manado, Indonesia, for the second Global Christian Forum (GCF).
Addressing the gathering, WCC moderator the Rev Dr Walter Altmann said the shared hope of Christians "must manifest itself in the relationships we nurture and the community that we build across traditions".
The GCF was inaugurated in Kenya in 2008 to forge new dialogue and relational encounters between churches and organisations where these have not traditionally existed.
The forum brings together representatives of various Christian traditions, including the WCC, the World Evangelical Alliance and the Pontifical Council for Promoting Christian Unity.
This meeting of the GCF has been organised by the churches in Indonesia and in particular the Communion of Churches in Indonesia.
Delegates were welcomed to the country during a reception hosted by the governor of North Sulawesi province, Dr S H Sarundayang.
The first day of the meeting on Wednesday was spent reviewing the history of the GCF, its strengths, and the potential of encounter and dialogue for transformation.
An important part of the GCF is time given over to small group meetings allowing delegates to share their faith journeys with one another.
Plenary sessions will examine major trends in world Christianity and the theme of the meeting, "Life Together in Jesus Christ, Empowered by the Holy Spirit".
The three-day meeting wraps up on Friday.