In 1925 he became head of the Ez Hayyim Yeshivah in Jerusalem. In Erez Israel, he devoted himself almost entirely to the dissemination of Torah and the strengthening of yeshivot. In 1935 his first work appeared, Even ha-Ezel on the Mishneh Torah of Maimonides which is regarded as a fundamental work of its kind. Seven volumes appeared during his lifetime, the other posthumously. He also edited and wrote commentary to the novellae of Nahmanides (1928/29).