The Torah commands the Kohanim and Leviyim in Parashat Korah (Bamidbar 18:5), “U’shmartem Et Mishmeret Ha’kodesh” (“You shall stand guard at the Sanctuary”), establishing a command to guard the Bet Ha’mikdash. Now this command has already been presented in the previous verse – “Ve’shameru Et Mishmeret Ohel Mo’ed” – and the Sefer Ha’hinuch lists that requirement as the 388 th Biblical command. This second verse is understood as introducing a Misvat Lo Ta’aseh (prohibition), forbidding the Kohanim and Leviyim from neglecting their duties and failing to stand guard. As mentioned in our discussion of Misva #388, the Kohanim and Leviyim were to stand guard not to protect the Bet Ha’mikdash from thieves or marauders, but rather as a display of honor. Needless to say, G-d does not need human beings to protect His Sanctuary; the guards were present to lend an aura of respect and reverence for the sacred site, just as guards stand at palaces and other important places. The Sefer Ha’hinuch here addresses the question of why the earlier verse – “Ve’shameru Et Mishmeret Ohel Mo’ed” – is understood as introducing a Misvat Aseh (affirmative command), whereas this second verse is viewed as establishing a Misvat Lo Ta’aseh. On what basis, he asks, did the Sages decide which verse introduces which command? The Sefer Ha’hinuch answers that Misvot Lo Ta’aseh are stricter than Misvot Aseh, in that one is liable to punishment for transgressing a Misvat Lo Ta’aseh, but not for neglecting a Misvat Aseh (with several exceptions). Therefore, when it comes to the two commands to guard the Bet Ha’mikdash, the verse which is formulated in stricter terms is understood as referring to a Misvat Lo Ta’aseh, and the verse which is formulated in milder terms refers to a Misvat Aseh. The second verse is written in the second person – “U’shmartem” (“You shall guard”) – which is a stronger, more direct formulation than the third person form used in the first verse – “Ve’shameru” (“They shall guard”). On this basis, the Sages understood that the first verse introduces a Misvat Aseh and the second verse introduces a Misvat Lo Ta’aseh. In any event, if the Kohanim and Leviyim fail to guard the Bet Ha’mikdash as required, then they are guilty of transgressing both a Misvat Aseh and a Misvat Lo Ta’aseh. They are not liable to Malkut, however, because this violation is committed passively, through inaction, by failing to perform a required act, and Malkut are administered only when one transgresses a Misvat Lo Ta’aseh by performing a forbidden action.