Marx is famously recorded as saying "religion is the opium of the people." He means as Westphal explains that when people endure deprivation they create gods to cope but that also the ruling class uses religion to legitimize their rule. Marx rightly notes that religion in some senses is both a mirror and a protest, however he is more interested in the way religion is abused by the ruling elites. Westphal notes that Marx's critique of religion is in one sense exploring the "cognitive dissonance" (p139) between ideology and reality. Is God "an enemy or ally of injustice" (p153)?
In this section I was interested by Marx's observations about the use of ideology in political rule. Marx writes: "The ideas of the ruling class are in every epoch the ruling ideas" (p 161). (Westphal tangentially and correctly notes at this point that ideology and religion are functionally identical.) Westphal seeks to use Marx's critique to untangle Christianity from its often abusive position of power because as "Jacques Derrida is aware 'a project can always be kidnapped, so to speak, or exploited for different political and cultural purposes'" (p172). Wesphal gives the example of Luther's support of the brutal suppression of the German presents revolt in the early 1500's. Westphal then explores how religion specifically Scripture is used by the ruling class to legitimate their rule. For example over-spiritualizing or maintaining a 'sinful silence'.
(Three part review of Suspicion and Faith: The Religious uses of Modern Atheism by Merold Westphal)