WCC general secretary Rev. Dr Konrad Raiser paid the following tribute to Dr de Lange:

The World Council of Churches is greatly saddened by the news that Dr Harry de Lange has passed away; in gratitude for his outstanding contributi on to the ecumenical movement, the Council offers its sincere condolences to his family and to the churches in the Netherlands, who have lost one of their ecumenical pioneers.

Almost from its creation in 1948, Dr de Lange became involved in the life and work of the WCC. He was one of a group of Dutch academics that included Prof. J. Tinbergen and Dr C.L. Patijn, and that quickly began contributing to WCC work in the field of "Church and Society". Dr de Lange also served for many years as a member of the board of the Ecumenical Institute at Bossey.

When a formal WCC working committee on "Church and Society" was established in 1954, Dr de Lange became an active member, and retained this membership until his retirement. Through him, the tradition of Dutch Christian social thinking was well represented in WCC "Church and Society" programmes and projects over the next three-plus decades.

Harry de Lange was among the influential minds at a 1966 Geneva conference on "Church and Society", and later at a 1979 WCC conference on "Faith, Science and the Future" that took place at the Massachusetts Institute of Technology (MIT). He was instrumental in setting up an advisory group on economic matters that shaped WCC policies and strategies in this particular area during the 1970s and 80s. It was his special concern to assure active representation and participation of voices from the southern hemisphere in WCC meetings, and he was a strong supporter of the thinking of such Christian leaders from the South as Prof. Sam Parmar and Dr M.M. Thomas, both from India.

After his retirement, Harry de Lange concentrated on the issue of justice in affluent Western societies. In 1995 with Prof. Bob Goudzwaard, he published a widely acclaimed study entitled Beyond Poverty and Affluence: Towards an Economy of Care. Translated into several languages, this book had a lasting influence on ecumenical social thought.

The WCC is greatly indebted to Dr Harry de Lange for his immense contributi on to ecumenical social thought. He was a teacher, a colleague and friend to several generations of ecumenical co-workers. He was also a model for trying to articulate, and live out, Christian responsibility in a period of rapid social change and growing social and economic inequalities. Dr de Lange will be remembered with gratitude and respect as one of those who paved the way for the contemporary social witness of the churches.