1,149. Blowing Shofar in the Temple

Hilchos Shofar, Succah v’Lulav 1:2

In the Temple, they would blow shofar on Rosh Hashana as follows: There was one shofar and two trumpets, one on either side. The sound of the shofar was lengthened and the sound of the trumpets was shortened because the mitzvah of the day is performed with a shofar. Trumpets were blown together with the shofar as per Psalms 98:6, “You shall sound trumpets and the voice of the shofar before God, the King.” In other places, only the shofar is blown on Rosh Hashana.

Hilchos Shofar, Succah v’Lulav 1:3

One should not blow a shofar that was used for idolatry but if one did so, he has fulfilled his obligation. However, if one blows a shofar from a condemned (idolatrous) city, he has not fulfilled his obligation. If someone blows a stolen shofar, he fulfills his obligation because the mitzvah is only to hear the sound; the listener doesn’t have to touch or lift the shofar at all and the laws of theft do not apply to sound alone. Similarly, a shofar from a burnt offering should not be blown but if one did so, he fulfills his obligation because the laws of misappropriation of sanctified items do not apply to sound alone. If you would suggest that the offender derived benefit from sanctified property by hearing the sound, the Rambam clarifies that performing mitzvos is not considered one's personal benefit. According to this logic, one who has vowed not to derive benefit from a shofar may blow it to perform the mitzvah.