Halakhah su Deuteronomio 21:10

While the Rambam does mention Levi's military exemption at the end of Hilchot Shemitah Veyoveil, it is uncertain how much weight this carries, because he does not present this rule in Hilchot Melachim, where he discusses military exemptions at length. In fact, the Radak (II Shmuel 23:20) claims that in wars against the enemies of Israel, even the Kohanim (the most sanctified part of the tribe of Levi), who ordinarily avoid contact with dead bodies, must take an active part in killing the enemy.²From the Radak's comment in I Melachim (2:25), it sounds as if he only believes that Kohanim are permitted (but not obligated) to take part in fighting enemies. However, he writes there that he is merely restating what he wrote in II Shmuel 23:20. David's great warrior, Benayahu ben Yehoyada, exemplified this practice. Despite being a Kohein, he served as a high-ranking officer in King David's army and eventually became the head of King Shlomo's army. Moreover, the Gemara (Kiddushin 21b) and the Rambam (Hilchot Melachim 8:4) discuss the laws of a Kohein who fights in wars, indicating that this was done in practice.³The Talmud discusses whether a Kohein is permitted to take an eishet yefat to'ar (see Devarim 21:10-14).