his creatio ex nihilo only comes into being because—and in as far as—the omnipotent and omnipresent God withdraws his presence and restricts his power. It was Isaac Luria who first of all developed these ideas in his doctrine of zimsum.25 Zimsum means concentration and contraction, and signifies a withdrawing of oneself into oneself. Luria was taking up the ancient Jewish doctrine of the Shekinah, according to which the infinite God can so contract his presence that he dwells in the temple. But Luria