Rabbinic literature on almsgiving centers on four themes—anonymous indirect giving, indiscriminate giving, justice for the poor, and the redemptive power of alms—which make up a comprehensive rationale for giving that was picked up by late antique advocates of Christian charity. Using the ninety-seven extant homilies of Leo I, bishop of Rome (440-461), I contrast the evidence for the Greco-Roman and Jewish models of gift-giving in the preaching and charitable activities of western bishops. First, I examine the four themes as they appear in rabbinic literature and in Leo's homilies. Second, I establish why one model of giving remained dominant in Rome in this period: that of redemptive almsgiving (i.e. giving alms in order to attain one's own salvation), a model that had become standard in western Christian texts on almsgiving by the end of the fourth century. The dominance of this model in the West, as evident in the homilies of bishops like Leo the Great, poses a significant challenge to the thesis posed by Patlagean and adopted by Brown, namely, that the rise of the virtue of charitable giving in the fourth and fifth centuries had a significant impact on social and economic relations between rich and poor. Evidence from hagiography, law codes, inscriptions, sermons, and letters presents rather a different picture, one of bishops upholding the status quo while preaching an impossible ideal of justice for the poor. The Derridean concept of the "impossibility of the gift" helps to illuminate how the Greco-Roman patronage model inhibited the emergence of a new way of thinking about and acting towards the poor in these centuries.