The religious views Magnes extolled as a Reform rabbi were not at all within the mainstream. Magnes favored a more traditional approach to Judaism, fearing the overly assimilationist tendencies of his peers. Magnes delivered a Passover sermon in 1910 at Congregation Emanu-El of the City of New York in which he advocated changes in the Reform ritual to incorporate elements of traditional Judaism, expressing his concern that younger members of the congregation were driven to seek spirituality in other religions that cannot be obtained at Congregation Emanu-El. He advocated for restoration of the Bar Mitzvah ceremony and criticized the "Union Prayer Book", advocating for a return to the traditional prayer book. The disagreement over this issue led him to resign from Congregation Emanu-El that year. From 1911–12 he was Rabbi of the Conservative Congregation B'nai Jeshurun.