"Christian Witness in a Multi-Religious World" is the first joint document of its kind in church history and seeks to identify not only the biblical call to evangelism but also the ethical mandates of Christian witness.
It offers recommendations for Christian conduct in the mission field and is a joined up response to criticisms levelled at Christians by some religious communities against what they perceive to be "unethical methods".
Its launch in Geneva, Switzerland, today comes follows five years of discussions between the WCC, WEA and the Vatican's Pontifical Council on Inter-religious Dialogue (PCID).
WEA Secretary General Dr Geoff Tunnicliffe said it was a "historic document" and a "historic moment" for the three bodies, who together represent more than 90 per cent of the world's total Christian population.
Dr Olav Fykse Tveit, General Secretary of the WCC said the document was a testimony to their search for unity.
He said the document would give "strength" to the joint witness of Christians to the Gospel.
"Christian witness demands Christian attitudes," he said.
President of the PCID, Jean-Louis Cardinal Tauran, stressed the need for a common voice in the face of challenges to proclaiming the Gospel and efforts to privatise faith.
"We are making history this afternoon," he said.
The preamble to the document starts by stating that mission belongs to the very being of the church.
"Proclaiming the word of God and witnessing to the world is essential for every Christian," it reads.
"At the same time, it is necessary to do so according to gospel principles, with full respect and love for all human beings."
The 12 principles its sets out for Christian witness include acting in God's love, living with integrity, compassion and humility, and rejecting violence.
Dr Tveit said it was important that Christians witness with the same "respect that Christ has shown to other human beings".
The document then goes on to make six recommendations to Christians, church bodies, mission organisations and agencies.
These are: to study the document; build respect and trust with people of all religions; strengthen religious identity and faith whilst deepening knowledge and understanding of different religions; advocate justice and respect for the common good; call on governments and representatives to ensure religious freedom for all people; pray for the wellbeing of neighbours; and recognise that prayer is integral to the Christian life and Christian mission.
On the issue of conversion, which has been a sore point for some in other faith communities, the three leaders stressed the right to choose.
Dr Tveit said: "Conversion cannot be imposed on anyone. I hope this is a clear message [we convey] through this document."
Cardinal Tauran added: "Conversion is God's freedom and man's freedom. It is a mystery. We cannot programme [it]."
Dr Tunnicliffe noted that in some sense there was "nothing new" in the document, but added that what was written down had "never been so clearly stated and within the context of [the WEA, the WCC, and the Vatican]".
He expressed his hope that it would build new bridges between Christians as well as with different faith communities.
"In some places dynamic public witness to Jesus Christ has been accompanied by misunderstanding and tension," he said.
"This document is a valuable resource for church and ministry leaders for reflection and practice on how to best witness in ways faithful to the call of Christ and in line with the life and Spirit of Jesus."
The document is to be passed down by the three bodies to their respective constituents for further consideration.
Dr Tunnicliffe said he hoped it would be the first of many such joint initiatives between the WEA, WCC and Vatican.