The present article tries to analyze the role played in Hans Jonas’ ethical reflection by religious—namely, Jewish—tradition. Jonas goes in search of an ultimate foundation for his ethics and his theory of the good in order to face the challenges currently posed by technology’s nihilistic attitude towards life and ethics. Jonas’ ethical investigation enters into the domain of metaphysics, which offers an incomparable contribution to the philosophical endeavour, without undermining its overall independence. In this way, Jewish categories—such as remorse, shame, sacrifice, repentance, and selfrestraint—strengthen the philosopher’s ethical reflection, since he considers them to be essential moral values for the technological epoch. Yet the reference to the Jewish tradition supplies Jonas’ ethical endeavour with a powerful but only hypothetical insight into transcendence.