The Feast of Trumpets of the Jewish calendar begins the evening of September 17 this year. Here in the United States, the name of the feast conjures up the brass section of an orchestra, perhaps, or of the straight trumpets used by English heralds even today. Christian art pictures the end of the world with Gabriel blowing the herald's trumpet, ignoring that the Christian scriptures never attribute such an action to Gabriel.
The actual "trumpet" in question, however, is the shofar. This is made from the horn of a clean animal other than the beef. Usually it is made of the horn of a ram or an antelope, but may be made of sheep or goat horn as well. It is particularly not to be straight, but must have at least some curve to it.
The Jewish sages further developed certain rules about the shofar. No alterations were to be made to the horn to improve its sound. While it may be decorated with metal designs, the interior of the horn was not to be lined with metal to make it sound better. Any holes were not to be covered so as to change the note of the horn. Further, it was not to be boiled or steamed in order to straighten or further curve it. In essence, it was to be a naturally occurring horn to give a natural note.
The directions for the Feast of Trumpets are found in Leviticus 23:24-25:
In the seventh month, in the first day of the month, shall ye have a sabbath, a memorial of blowing of shofars, an holy convocation. Ye shall do no servile work therein: but ye shall offer an offering made by fire unto the LORD.
No other command or explanation is given. Just blow the trumpet, make an offering, and do no constructive work. God doesn't explain his reasons, as he does for the Sabbath and Pesach (Passover). He commands, and that is it. There is one possible reason for the holiday that bears emphasizing.
One of the traditional uses of the shofar, indeed of the modern trumpet, is the sounding of a warning in times of danger. It can be heard at a much greater distance than a human voice, and be distinguished even in the babble of battle.
In the blowing of the shofar we are reminded that we are in danger. The adversary is approaching. We are in a battle with the Evil Inclination. Temptations surround us and besiege us daily. Once a year, ten days before the Day of Atonement, the shofar is sounded to remind people of sin and call them to repentance. Ten days, it says. Ten days and then comes Yom Kippur. Recall that you are in danger, and repent.
Jeremiah lived in a time of religious reform. The book of the Law had been found. The Temple worship and the calendar had been restored. And yet the people did not repent of their idolatry. They would worship at the Temple, and then go home to their shrines and idols. Perhaps it was around the start of the year, the Feast of Trumpets, when God told him (Jer 6:17), "Also I set watchmen over you, saying, Hearken to the sound of the trumpet. But they said, We will not hearken." Perhaps they had just come from hearing the 100 blasts of the shofar, and God was telling him that it had done no good. As a priest, perhaps even Jeremiah had been the person to blow the shofar, and now God was telling him that, just as the people had not listened to that horn, they would not listen to the man who was God's shofar, Jeremiah himself.
May God never say of us that we had ignored the sounding of the shofar. May we hear, and repent.