The aim of this article is to analyse the educational and spiritual legacy of Mordechai (Motti) Bar-Lev, one of the pillars of religious education research in Israel. We first analyse the ideological-theoretical foundations that underlay his thought and provided inspiration for his scientific writing. Next, we analyse the principal dilemmas on which he focused in his research, and finally we attempt to consider the special nature of his work and its contribution to religious education research. Bar-Lev's quantitative and qualitative research dealt with the elite of religious Zionism who grappled with traditionalism and modernity, and principally with its habitat--state religious education. Bar-Lev will be remembered not only as having informed the field of religious education in Israel, but, most of all, as the researcher who shaped its future.