Negative commandment · Lo Ta’aseh #67 of 613
Not to interrupt the watch held around the Temple
שלא להשבית שמירה סביב למקדש
The verse · Vayikra 18:30
וּשְׁמַרְתֶּם אֶת־מִשְׁמַרְתִּי לְבִלְתִּי עֲשׂוֹת מֵחֻקּוֹת הַתּוֹעֵבֹת אֲשֶׁר נַעֲשׂוּ לִפְנֵיכֶם וְלֹא תִטַּמְּאוּ בָּהֶם אֲנִי ה׳ אֱלֹהֵיכֶם
“Therefore shall you keep my ordinance, that you commit not any one of these abominable customs, which were practised before you, and that you defile not yourselves in them: I am the Lord your God.”
The Rambam’s words
Not to interrupt the watch held around the Temple, as [Leviticus 18:30] states: "And you shall keep My watch." it appears to be an error, because the passage it introduces deals with sexual offenses. In Sefer HaMitzvot, the Rambam quotes as a prooftext Numbers 18:5, "And you shall keep the watch over the holy articles."
שלא להשבית שמירה סביב למקדש, שנאמר "וּשְׁמַרְתֶּם אֶת מִשְׁמַרְתִּי" (ויקרא יח, ל).
Where in the Mishneh Torah
Hilchot The Chosen Temple הלכות בית הבחירה