This article explores the religious importance of Cicero's De Haruspicum Responso against the background of prodigy-handling in Republican Rome. Comparing the prodigy in question to an ‘auditory epiphany’, it argues that key issues raised by the speech include the nature of the divine voice, the relationship of the prodigious ‘rumbling and clattering’ to the gods themselves, and the ambiguous temporalities implied by Roman practices of divination. The article also suggests that De Haruspicum Responso proposes a significant overlap between religious and political speech, and it questions the radical split often assumed between the religious ideology of Cicero's philosophical and his more ‘public’ works.