This paper sketches an evidential atheological argument that can be answered only if one of the central tenets of some theistic traditions is rejected, namely, that (propositional) belief in God is a necessary condition for salvation. The basic structure of the argument is as follows. Under theism, God is essentially omniscient, but no one can be both omniscient and irrational. So, if there is reason to hold that God is irrational, then it would follow that God doesn't exist. And there is reason to hold that God is irrational. To wit, God both hides and, according to some theistic traditions, requires belief. But it is irrational for God both to hide and require belief; therefore, God is irrational. Since a crucial – and controversial – premise in the argument is that it is irrational for God both to hide and require belief, a large part of the paper is devoted to defending that premise.