Ernst Bloch... recognized the dual character of the religious phenomenon, its oppressive aspect as well as its potential for revolt. The first requires the use of what he called 'the cold stream of Marxism': the relentless materialist analysis of ideologies, idols and idolatries. The second, however, requires 'the warm stream of Marxism', seeking to rescue religion's utopian cultural surplus, its critical and anticipatory force.
p. 16 - The War of Gods: Religion and Politics in Latin America (1996)