“Praiseworthy is the nation that knows how to blow the trumpet” (Tehillim 89:16).The Sages remark about this verse: Do not all nations know how to blow trumpets?! Only, the verse means to praise the Jewish people for knowing how to appease Hashem by means of the shofar (Vayikra Rabbah 29:3). Rashi explains that the Jewish people know to accompany the shofar-blowing with verses of Kingship, Shofar, and Remembrance. In other words, by reciting verses of Kingship, we show that we are blowing the shofar to coronate our king. By reciting verses of Shofar, we show that we are blowing the shofar to recall our King’s awesome glory, which was displayed through the shofar-blowing at the time of the Giving of the Torah and which will displayed through the shofar-blowing in the future. And by reciting verses of Remembrance, we show that we are blowing the shofar to recall our King’s merciful remembrance of our merits, and especially the merit of the ram that was offered instead of Yitzchak. Only the Jewish people know how to appease Hashem in this unique manner.

By blowing the shofar, we are not only “reminding” Hashem about these ideas; we are reminding ourselves as well. When we blow the shofar with these intentions, we joyously submit our lives to Hashem’s will in emulation of that self-sacrifice of our Patriarch, and that is why He becomes appeased and sees fit to pardon our misdeeds. Rav Shalom Sharabi writes (cited in Avodas Rosh Hashanah ch. 8): “The sound of the shofar does not have an effect in Heaven unless its sound rises with the awakening of the heart in repentance. Otherwise, it is like blowing a musical instrument.”

As to the nature of this awakening, Rambam writes that the shofar calls to us: "Awaken slumberers! Examine your deeds, remember your Creator, and return to Him! You who have forgotten the truth amidst the temporal vanities of this world and have spent the year in worthless pursuits, consider your souls, rectify your deeds, and abandon your improper thoughts!” (Teshuvah 3:4). Sefer HaChinuch elaborates on the need for a reminder: Since a person is earthly, he does not awaken to [spritual] matters unless by means of some awakening device. This is the idea behind the battle cries and trumpet blasts of soldiers when they want to awaken their spirits in order to maximize their performance. We are in similar danger on Rosh Hashanah, when our lives are on balance, and the broken shofar sounds (i.e., teruah)shake our hearts awake with repentance.

Sefer HaChinuch adds that the broken sounds remind us to "break" the evil inclination of our hearts that urges us to pursue earthly pleasure and sins. We use the medium of sound because it has a great influence on emotion. We specifically use a ram's horn, which is bent, to remind ourselves to bend our hearts into submission to Hashem.

The Midrash (Vayikra Rabbah 29:5 with Radal) relates the word “shofar” to “shippur,” meaning “beautification” (Radak in Sefer HaSharashim), and it thus expounds as follows: In this month of Tishrei, beautify your deeds and adopt a new conduct. Hashem says: “If you have beautified your deeds, I will be for you like a shofar. Just as air enters the narrow side of the shofar and exits through the wide side, so too, I will stand up from My Throne of Justice and sit down on My Throne of Mercy, transforming the Attribute of Strict Justice into the Attribute of Mercy.” Every shofar blast breaks away another layer of our evil inclination and with the completion of the hundred blasts, we experience rebirth. For just like childbirth may entail a hundred cries, with the hundredth bringing new life (Tanchuma to Tazria §4), every cry of the shofar brings us toward repentance, with the hundredth bringing us to full repentance, and a new year of good life (Meshech Chachmah to Vayikra 23:24).”