The article is a response to Dana Robert’s keynote address "One Christ – Many witnesses: Visions of Mission and Unity, Edinburgh and Beyond" at the Celebration Symposium of the Regnum Edinburgh Centenary Series, 4 September 2015 in Oxford. The author wonders whether Dana Robert has sufficiently taken into account the awareness in the World Council of Churches of the diversity in and among Christian traditions. He highlights the more dynamic understanding of unity, which does not find expression in new (super-)structures but in a commitment to travel together in a pilgrimage of justice and peace.