This paper argues and demonstrates that Calvinism, contradicting its claim to be the only true Christian and reformed religion, reverses the Christian Biblical injunction and desideratum that the "last shall be the first". In terms of social stratification, this injunction represents the mass social-psychological manifestation of the revolt of oppressed social classes against their oppressor class. Calvinism, by effectively inverting it into the "first shall remain the first", becomes an expression and justification of oppression and domination by the ruling social class over other classes. The main argument is that orthodox Calvinism constitutes both the product of a social stratification system in which the "first shall be the first" and, once established as the predominant religion, the religious and ideological reproducer of such a system of perpetual and widespread societal inequality, including economic and political. Specific hypotheses specify this argument with respect to particular dimensions of the system of social stratification. Both historical observations and comparative data largely support the argument and hypotheses. Especially, comparative data confirm that the legacy of Calvinism, including Puritanism, in the US and other historically Calvinist/Puritan countries is pervasive wealth and income inequality and persistent and widespread poverty by comparison to most Western and comparable societies.