Yoel, 30, is what was called in the 90s a Lubavitch, an Orthodox Jew. Every Saturday morning, he goes, accompanied by his 6-year-old son, to honor Shabbat in the synagogue in his neighborhood, a primary school set up for the occasion. That day, the rabbi of the community of devotees, Rav Kalmenson, an impressive man with his charisma and his long beard, will challenge Yoel by announcing to him that his son is lighting up.