The Torah itself establishes the day as one of alarm and awakening: Bamidbar 29:1 designates Rosh Hashanah as "a day of teruah," and the Mishneh Torah, Shofar, Sukkah and Lulav 1:1 derives from this verse the positive Torah obligation to hear the shofar's blast.
The Gemara in Rosh Hashanah 16a presents God's own reasoning: the shofar brings before us the themes of Kingship, Remembrance, and Shofarot — we sound it to crown God as King, so that our remembrance rises before Him for good, and specifically because a ram's horn recalls the Binding of Yitzchak, whose merit we invoke on our behalf.
The Rambam, Mishneh Torah, Repentance 3:4 makes the wake-up call explicit: although the shofar is a Scriptural decree, it carries an allusion — "Awake, you sleepers, from your sleep; you who slumber, rouse yourselves from your slumber; search your deeds and return in repentance, and remember your Creator."
The Sefer HaChinukh explains the shofar's psychological function in two places: Sefer HaChinukh 405 reasons that because a person is physical and is only aroused by an external stimulus — just as soldiers are stirred for battle by trumpet blasts — the shofar is needed on the very day all creatures pass before God in judgment; and Sefer HaChinukh 384 similarly notes that human nature, without an awakener, stands like one asleep, requiring powerful arousal both at moments of sacrifice and moments of distress.
The sound's inner character is explored by several sources: Rosh Hashanah 33b derives from the weeping of Sisera's mother that the teruah mimics broken, wailing sighs, while Rosh Hashanah 26b records a dispute over the shofar's shape — one view holding that on Rosh Hashanah the more a person bends his mind and humbles himself the better, the other that the more he straightens his mind the better — both positions treating the shofar's physical form as a mirror of the inner disposition one should bring to the day.
The Gemara in Rosh Hashanah 16b adds that the double blowing — once before the Amidah and once within it — is specifically intended to confuse the Satan, demonstrating Israel's love of the commandment and thereby securing a favorable judgment; and Rosh Hashanah 26a notes that because the shofar is sounded to evoke God's remembrance, it is treated as though it were sounded inside the Holy of Holies itself.
The liturgical framework surrounding the shofar reinforces its meaning: the Yalkut Shimoni on Torah 725 establishes that Malkhuyot precedes Zikhronot and Shofarot so that one first crowns God as King before bringing one's remembrance before Him, and Rosh Hashanah 32b–33b rules that only verses of remembrance and shofar that evoke hope — not calamity — may be recited in the Rosh Hashanah prayers.
The Acharonim deepen the meaning further: רש"ר הירש, ויקרא כג כד, וראה שם עוד reads the sequence of tekiah-teruah-tekiah as a three-part message — the opening tekiah calls one to listen to God's word, the teruah summons one to break from every stance that is evil in God's eyes, and the closing tekiah calls one forward to a new and faithful walk with God; רש"ר הירש, תהלים קן ג and רש"ר הירש, תהלים קנ ג both characterize the shofar as the instrument that is serious and calls the person to God, distinct from instruments that express joy or intellectual reflection.
Hasidic thought locates the shofar's power in the wordless voice itself: the Sefat Emet, Devarim, Rosh HaShanah 17 teaches that the shofar is the distinctive voice of Israel — not articulated speech shaped by the human intellect but a simple, raw sound — signaling that Israel's strength is a gift from God, and that this voice possesses a grace in heaven that arouses divine mercy; Likkutei Torah, Rosh Hashanah 56c–57a adds that the tekiah is a simple sound rising from the innermost depth of the heart, representing a cry that transcends the level of speech and wisdom entirely.
מכתב מאליהו, חלק ב עמוד עג draws on Rav Saadia Gaon's ten intentions for the shofar, among them the memory of the Akeidah — through which one accepts upon oneself to give one's life for the sanctification of God's name — and cites the Zohar's teaching that the verse "happy is the people that knows the teruah" specifies knowing, not merely hearing or sounding, because the secret of the teruah is an elevation of the heart to cleave to that level, and it is through this inner knowing that one is drawn close to God's light.
Machshavot Charutz 18:9 frames the shofar's sound as a rectification of the primordial failure of Adam, who heard the voice of God but did not follow it; we hear the shofar through our own initiative from below and are drawn after it, arriving at awe of God and the recognition that everything comes only from Him — an inner repair accomplished in the heart through the hearing itself.
Maamar HaChochmah, Chelek 1 6:6 places the Rosh Hashanah shofar within a vast arc: the shofar at Sinai inaugurated the strengthening of good in the world, the great shofar of the future will complete that repair, and the annual blowing on Rosh Hashanah comes to reinforce what was established at Sinai and to prepare for what is yet to come.
Resisei Layla 51:1 explains that the shofar is the vehicle through which Malkhuyot, Zikhronot, and Shofarot actually accomplish their work — recognizing God as King completes creation, recognizing His providence draws His watchful care toward good, and the shofar itself confounds the prosecuting force, carrying the power of the future shofar that will herald ultimate redemption.
Finally, the halakhic framework insists that hearing requires conscious intent: Shulchan Arukh, Orach Chayim 589:8 rules that the listener and the blower must both direct their minds toward fulfilling the obligation, and Rosh Hashanah 29 confirms that neither party's intent alone suffices; the Mishnah Berurah 585 notes that the blessing is phrased "to hear" precisely because the entire obligation rests on hearing — one who blows but does not hear has not fulfilled the commandment at all — pointing the worshipper toward active, engaged listening rather than passive presence.
