This article revisits a set of classic political, theological and economic scenes in the (early) modern debate on usury from Luther to Bentham. To summarize, I argue that this theory of usury – which polemically mobilizes counter-Aristotelian tropes of the breeding, reproduction and husbandry of money – might also be read as a theory of what Foucault famously calls pastoral power. If this debate nominally concerns the ‘repeal’ of the ancient prohibition against money-lending at interest, I argue that what is really at stake here is the pastoral production of a new theory of the subject as ‘human interest’: a self whose allegedly intrinsic self-interest expresses itself paradigmatically through financial interest. In conclusion, I situate this genealogy of human interest within the larger history of the self-interested, capitalist and indebted subject from Hirschman, through Foucault, to Lazzarato.