In both Plato and Thomas Aquinas, we find proposals to understand piety or religion as justice toward God/the gods. One issue with this proposal is what can be called the problem of human-divine reciprocity: Since justice would seem to require human beings to make a return for what they have received from God/the gods, how can this be done without implying God/the gods lack something that human beings can supply? I outline the account of piety/religion as justice toward the divine (...) in both Plato and Aquinas, noting how the reciprocity problem arises along the way. Then I defend a proposed solution drawn from Aquinas: that glory, or the manifestation of divine goodness, is what God seeks in pious human action, yet without implying any benefit to God thereby. (shrink)