Whether or not the modern Westerner wishes to believe in the real existence of infernal realms is in a sense beside the point. Evil simply brings forth suffering; and it hardly matters whether one conceives of this in the picturesque terms of Dante’s Inferno or shares the view of Jean-Paul Sartre that “hell is other people.” Nevertheless, it is important to grasp that the idea of eternal damnation as a punishment for sin is foreign to Buddhist understanding. Suffering is a consequence of one’s own action, not a retribution inflicted by an external power. Infernal torments, moreover, though they may last for aeons, belong to samsara and are therefore not exempt from the law of impermanence. And even if the notion of a divine vengeance is regarded as an approximation, in mythological terms, to the concept of karmic consequences, it is perhaps worth suggesting that the impersonal view proposed by Buddhism should have the advantage of exorcising the paralyzing sense of guilt, or revolt, that can so often be the outcome of a too anthropomorphic theism. The doctrine of karma has only one message: the experience of states of being follows upon the perpetration of acts. We are the authors of our own destiny; and being the authors, we are ultimately, perhaps frighteningly, free.
--from the Padmakara Translation Group’s Introduction to Shantideva’s Bodhicharyavatara (Guide to the Bodhisattva’s Way of Life) (Shambhala Publications, 1996).