384. Sound Off: The obligation to sound trumpets in the Temple and for war

It was a mitzvah to sound trumpets every day in the Temple when the daily sacrifices were offered; it was also a mitzvah to sound them in times of communal crisis, such as going to war. (The Torah also says that they are to be blown on holidays and on Rosh Chodesh, but that means over the musaf offerings of those days just like over the regular daily sacrifices.)

The Talmud tells us (Menachos 28a) that only trumpets made of silver were acceptable for this purpose. A minimum of two trumpets had to be kept in the Temple, not to exceed 120 (Arachin 13b). The minimum number of trumpet blasts in the Temple on any given day was 21 and the maximum was 48 (Arachin 10a). It appears that the blowing of the trumpets was carried out by kohanim (priests), not Levites (as per Numbers 10:8), though there may be different views on the matter.

The reason for this mitzvah was to focus the attention of the kohanim on the sacrifices. As was discussed in Mitzvah #144, certain improper thoughts, such as to eat from a sacrifice in the wrong place or at the wrong time, would invalidate the service. The trumpets were a huge, “Hey, you!” to the kohanim, drawing their concentration to the service so that it should be performed properly. Much as the shofar on Rosh Hashana is meant to draw our hearts to teshuva (repentance), the daily trumpet blasts in the Temple are meant to turn the minds of the kohanim to the spiritual importance their duties.

This mitzvah applies to Kohanim at a time when the Temple service is in effect. It is discussed in the Talmud in a variety of places including tractate Rosh Hashana (starting on page 26b). This mitzvah is codified in the Mishneh Torah in the first chapter of Hilchos Taaniyos. It is #59 of the 248 positive mitzvos in the Rambam’s Sefer HaMitzvos.