Shofar in Elul שופר באלול

Rabbi Yehoshua ben Karcha says: … On Rosh Chodesh Elul the Holy One, blessed be He, said to him [Moshe] “Ascend to Me to the mountain,” (Shemot 24:12) and they blasted the shofar in the camp, for Moshe had gone up to the mountain, so they would not stray after false gods anymore. And the Holy One, blessed be He, was exalted on that day with the blast of that shofar, as it says, “God has been exalted with the blast.” Therefore, the sages established that we blow the shofar on Rosh Chodesh Elul each and every year.

REMA The custom of the people of Ashkenaz is…from Rosh Chodesh and on we begin to blow (the shofar) after the shacharit prayer.

The Sages enacted the blowing of the shofar on Rosh Chodesh Elul every year, and the entire month, to warn Israel to repent, as it says “If a shofar is blown in the city [will the people not quake?!], (Amos 3), and also to befuddle the Satan.

It is understood that the blast of the shofar causes a person to quake from fear of God and from the glory of His might.

Even though blowing the shofar on Rosh Hashana is a Torah decree, it also contains an allusion. Namely, “Wake up you sleepers from your slumber and the unconscious from your stupor and search your ways and return in repentance and remember your Creator!” These are the people who forget the truth in the transience of time and waste all their years in futility and emptiness which does not have purpose and will not save them, look at yourselves and improve your ways and your actions and each one of you should leave your evil ways and thoughts that are not good.”

Because the shofar saved Israel from sin and the month of Elul is a month intended for teshuva, for it is the last month of the year and before the Days of Judgment. The sages of musar hinted at this from the verse “I am my Beloved’s and my Beloved is mine” whose initial letters form the word “Elul,” which is to say that now is the time when all of my thoughts should be toward my Beloved, and when I do this, then my Beloved is also mine, for He watches over me for my benefit. Also, the shofar is capable of [eliciting] teshuva…Therefore all of Israel have adopted the practice of blowing the shofar after prayer for this entire month.

In order to befuddle [the Satan]. That he not prosecute [against the Jewish people] when he hears that Israel cherish the mitzvot, his words are stopped up:

In any event, each person is obligated to prepare themselves with teshuva and prayer for thirty days prior to the day they enter into judgment before God on Rosh Hashana. And they should give their entire heart only to the service of God. And they alluded to this [with the verse] Ani le-dodi ve-dodi li, I am my Beloved’s and my Beloved is mine (Shir Hashirim 6:3) which is an acronym for Elul. Therefore, one should increase one’s teshuva, prayer and charity throughout the month.