DEUT1106 [This] commandment obligates Jews to return any lost object, much more so than any other society. One cannot merely walk by a lost object and ignore it (See chapter "Returning Found Objects"). The Talmud (Bava Kamma 91a) states that this mitzvah is not limited to physical objects. If a person has lost his or her away on the road, this falls under the obligation of returning a lost object. A Jew is obligated to help the person find the way back. According to many opinions (Among others, Minchat Chinuch, Mitzvah #239), the obligation to return someone's Judaism also falls under this obligation. Since at one time everyone had the "proper" spirituality, people who no longer feel the importance of Judaism have "lost" this feeling of Judaism. Therefore, the return of Jewish spirituality to a Jew falls under the commandment to return any lost object to a Jew. Perhaps this is why the process of coming closer to Judaism is called teshuvah, returning, and one who returns is called a baal teshuvah.