We study the production and circulation of arguments justifying actions on the basis of morality. By downplaying externalities, exculpatory narratives allow people to maintain a positive image while acting selfishly. Conversely, responsibilizing narratives raise both direct and reputational stakes, fostering prosocial behavior. These rationales diffuse along a linear network, through both costly signaling and strategic disclosure. The norms that emerge reflect local correlation in agents’ incentives (reputation versus influence concerns), with low mixing generating both a polarization of beliefs across groups and less moral behavior on average. Imperatives (general precepts) constitute an alternative mode of moral influence. We analyze their costs and benefits relative to those of narratives, and when the two will be used as substitutes or complements.