He was offered the Chair of Mission and Ecumenics at Princeton Theological Seminary in New Jersey, United States but chose to remain working against apartheid from within South Africa and the NGK. In 1979 he helped coordinate a gathering of more than 5000 African Christians from every background as a demonstration of the church as an alternative community embodying the Kingdom of God. In 1982 he promoted an open letter to the Dutch Reformed Church, signed by more than 100 pastors and theologians, publicly condemning apartheid and calling on the church to unite with black churches.