When Jürgen Moltmann's Theology of Hope first appeared in 1965, it was seen as ushering in a new era of theological thinking. Karl Barth, however, sharply criticised the work as too heavily dominated by a ‘principle of hope’ that he believed Moltmann had inherited from the Marxist philosopher Ernst Bloch. This interpretation has largely been taken as fact among interpreters of Moltmann's theology of hope. This has caused most interpreters to see his turn to panentheism and ecotheology in God in Creation (1983) as being less of a shift of emphasis than a total change of trajectory or even break. There is evidence, however, that a different source contributed to the overall orientation of Moltmann's theology – an orientation that has remained throughout his life. This other source is the life and thought of the radical Schwäbean Pietists, Johann Christoph Blumhardt (1805–80) and his son Christoph Blumhardt (1842–1919). In this article the authors flesh out the thesis that the Blumhardts are the prior, deeper and more long-lasting influence on Moltmann by focusing on three key theological motifs that permeate his theology: 1) Christianity as eschatology; 2) the ‘theology of the earth’; and 3) the ethics of hope. Furthermore, they argue that when the ‘hidden’ influence of the Blumhardts is acknowledged, Moltmann's later ‘shift’ can be understood as essentially in continuity, rather than discontinuity, with his earlier thought.