This essay seeks to examine Jean-Luc Nancy’s notion of “world”—alongside the one developed less explicitly by Giorgio Agamben—as an engagement with Christianity that is not simply “deconstructive” but so heretical as to exceed most recognized heretical positions. Nancy’s stylistic intermingling of prepositional and ontological formulations tends to obscure a doctrinal confrontation with Christianity on three related and foundational points: world, creator-creation, and eternity-time. In this regard, the claim to be “deconstructing” Christianity is a rather self-disarming softening of some otherwise exceptionally contentious claims. Whereas Nancy’s collapsing of the major Christian interpretations of world, creation, and eternity into something resembling their opposite makes his work on Christianity difficult to situate within established heretical traditions, Agamben’s persistent attention precisely to the split between the divine and the worldly, even if it is to show the points at which such a division is inoperative, places his thought much more squarely into the domain of dualistic heresies.