067 - המצווה הס"ז - האזהרה שהזהרנו מלהשבית שמירת המקדש ולסב בו תמיד כל לילה

This prohibition is that we have been warned never to cease guarding the Mikdash. In other words, there is a negative commandment not to stop the שמירת המקדש—guarding of the Holy Temple. This also includes the requirement to constantly circle around it every night, ensuring that the Mikdash is always protected and never left unattended.

The Torah is very specific about this obligation. It's not just a matter of having guards present, but that the guarding should be continuous, especially at night, when there is a greater concern for neglect. This mitzvah underscores the importance of maintaining the sanctity and security of the Mikdash at all times.

The source for this mitzvah is the verse, ושמרתם את משמרת הקדש—"You shall guard the Holy Guard"—from Bamidbar, chapter 18, verse 5. This phrase is the Torah's explicit command that the Mikdash must be guarded.

The wording here, ושמרתם, emphasizes the act of guarding as a sacred responsibility. The Torah uses this language to highlight that the guarding itself is not just a practical matter, but a holy duty connected to the sanctity of the Mikdash.

Earlier, in the 22nd mitzvah among the positive commandments, we already explained that guarding the Mikdash and circling it is a mitzvah aseh—a positive commandment. That means there is an active obligation to ensure the Mikdash is watched over.

However, here the Rambam clarifies that neglecting this duty—failing to guard or circle the Mikdash—is not just a lack of fulfilling a positive commandment, but it actually becomes a mitzvas lo sa'aseh, a prohibition. In other words, not guarding the Mikdash is a violation of a negative commandment as well.

This distinction is important: the same act—guarding the Mikdash—carries both a positive and a negative aspect. Fulfilling it is a mitzvah aseh, and neglecting it is a lo sa'aseh.

The language of the Mikhilta is brought here to clarify the source of this prohibition. The Mikhilta comments on the verse, ושמרו את משמרת אהל מועד—"They shall guard the guarding of the Tent of Meeting." From this verse alone, we would only know that guarding is a positive commandment.

The question then arises: How do we know that there is also a prohibition—a negative commandment—not to neglect the guarding of the Mikdash? The Mikhilta is pointing out that the verse itself seems to only indicate a mitzvah aseh, so we need a source for the lo sa'aseh.

The answer is that the Torah says, ושמרתם את משמרת הקדש—"You shall guard the Holy Guard." The use of the word ושמרתם—"you shall guard"—is understood by the Sages to also imply a prohibition. In other words, the Torah is not only telling us to do something, but also warning us not to neglect it.

This is a classic example of how the Torah sometimes uses the same wording to teach both a positive and a negative commandment, depending on the context and the way the Sages interpret the language.

The details of this mitzvah—how the guarding is to be done, who is responsible, and the specific procedures—are explained at the beginning of Tractate Tamid and Tractate Midos. These sections of the Gemara lay out the practical aspects of how the guarding of the Mikdash was organized and carried out in the Beis HaMikdash.

If you want to understand the halachic details of this mitzvah, you would look to those tractates for the full discussion and description of the procedures involved.