Sefer HaChinuch ספר החינוך

The commandment of blowing the trumpets in the Temple and in war: To blow trumpets in the Temple each day as every sacrifice is offered, and also at a time of troubles, as it is stated (Numbers 10:9), “When you come to war, etc.” and it is written after it also (Numbers 10:10), “And on your joyous occasions, and your fixed festivals and new moon days, you shall blow the trumpets over your burnt-offerings and over the sacrifices of your peace-offerings, etc.” And even though the verse warns about a joyous occasion, a fixed festival and a new moon day, this is not precise. As they would blow with the trumpets over the sacrifice every day in the Temple. And so is it explained in Rosh HaShanah 29a: “Everyone is obligated in the blowing of the shofar — priests, Levites, and Israelites.” And the Talmud wonders about this in the Gemara, “Is this not obvious? [For] if they are not obligated, who would be obligated?” And it responds to it, “It was necessary [to say] priests, for it may enter your mind to say, ‘Since it is written (Numbers 29:1), “It is a day of blowing, etc.,” [you might have said that with regard to one who is obligated to sound only one day, he is obligated to sound the shofar on Rosh HaShanah.] But these priests, since they are [obligated] all year long, as it is written (Numbers 10:10), “you shall blow the trumpets over your burnt-offerings and over the sacrifices of your peace-offerings, etc.” [you might say that they are not obligated].’” The Talmud then asks, “Are they similar? There it is a trumpet and here it is a shofar!” Nevertheless, we learned [from this] that throughout the whole year — meaning to say on each and every day — there were trumpets in the Temple. And they said in Tractate Arakhin 13a that we do not reduce to less than twenty-one blasts in the Temple and we do not increase to over forty-eight.

It is from the roots of the commandment that [it is] since at the time of the sacrifice they would need to properly focus their attention — as it is well-known that it is disqualified by certain thoughts — and also [that] the sacrifice requires complete awareness in front of the Master of all Who commanded about them; and also at the time of trouble, a person needs great focus in his supplication before his Creator, that He should have mercy upon him and save him from his trouble; we are therefore commanded to blow the trumpets at these times. As since man is physical, he requires great arousal to these things. For the way of nature is to stand asleep, and there is nothing as arousing as the sounds of music, [as is] well-known — and all the more so, the sounds of trumpets, which is the greatest sound of all musical instruments. And there is also another purpose, aside from arousal to focusing attention, that is realized through the sound of the trumpet; and that is that the sound of the trumpets removes all other worldly concerns from the heart of the listener, such that at that time he will only [direct] his heart to the matter of the sacrifice. But why should I go on so long? This is well-known to anyone who has ever bent his ear to hear, with focus, the trumpets or the sound of a shofar.

From the laws of the commandment — that which they, may their memory be blessed, said (Menachot 28a) that the trumpets came from a block of silver, as [indicated] in Scripture, and [if it is] from other types of metals, it is disqualified; that which they, may their memory be blessed, said (Arakhin 13a) that we do not ever reduce to less than two trumpets in the Temple and we do not increase above one hundred and twenty; and the rest of its details — are elucidated in Sifrei Bamidbar 77 (in Parashat Behaalotecha) and in Tractate Rosh Hashanah. And also in Tractate Taanit (Taanit 19a), the Sages elucidated that we are commanded to blow the trumpets at a time of trouble. (See Mishneh Torah, Laws of Fasts 1.)