There are many profound explanations that explore the symbolism of the mitzvah of tekiat shofar. One of the more famous expositions is that of Rambam. He writes:

Even though the sounding of the shofar on Rosh HaShanah is a decree, it contains an allusion. As if to say, ‘Wake up you sleepers from your slumber and dreamers from your sleep. Inspect your deeds, repent and remember your Creator…
(Hilchot Teshuvah 3:4)

According to Rambam the sounding of the shofar is a spiritual alarm clock. Something we all could use.

The shofar is supposed to sound like wailing and groaning. The Talmud (TB Rosh HaShanah 33b), in describing this crying sound, cites a verse which describes the tears of the mother of Sisera, as found in the song of Devorah, the fifth chapter of the Book of Shoftim.

Sisera was the general of Yavin, a Canaanite king. When the Jewish People wage war against him, led by Barak and Devorah, Sisera flees. He takes refuge in the tent of Yael who lures him in with warm milk and a comfortable bed. He meets his fate as Yael drives a tent peg into his skull after he is lulled into a sleep.

What does this story have to do with Rosh HaShanah?

In fact, Tosafot (ad loc.), based on a passage in the Talmud Yerushalmi explains that our custom of blowing one hundred blasts is because of the one hundred tears shed by Sisera’s mother.

On our most holy day, why evoke the mother of the wicked Siserah?

You can imagine the scene: Siserah’s mother waiting by the window, filled with uncertainty. Wondering, asking herself: will he come home? Knowing quite well she will ever see him again.

The Rav, Rabbi Yosef Dov HaLevi Soloveitchik explained that when we hear the sound of the Shofar we awaken from spiritual complacency. Our illusions are “relentlessly shattered.” Everything we took for granted or assumed comes crashing down like a house of cards.

During one of his marathon five hour Teshuvah lectures, the Rav, Rabbi Yosef Dov HaLevi Soloveitchik shared something very personal to illustrate this point:

On the seventh day of Pesach, 5727 (1967) I awoke from a fitful sleep. A thunderstorm was raging outside, and the wind and rain blew angrily through the window of my room. Half awake, I quickly jumped to my feet and closed the window. I then thought to myself that my wife was sleeping downstairs in the sun room next to the parlor, and I remembered that the window was left open there as well. She could catch pneumonia, which in her weakened physical condition would be devastating.

I ran downstairs, rushed into her room, and slammed the window shut. I turned around to see whether she had awoken from the storm or if she was still sleeping. I found the room empty, the couch where she slept neatly covered.

In reality she had passed away the previous month.

The most tragic and frightening experience was the shock that Iencountered in that half second that I turned from the window to find the room empty. I was certain that a few hours earlier I had been speaking with her, and that at about 10 o’clock she said good night and retired to her room. I could not understand why the room was empty. I thought to myself, ‘I just spoke with her. I just said good night to her. Where is she?’
(Before Hashem You Shall Be Purified: Rabbi Joseph B. Soloveitchik on the Days of Awe by Arnold Lustiger, p. 8-9)

The Rav explained that the shofar shakes us to our core:

We are jolted with the sudden awareness of the greivous extent to which our actions have alienated us from God…We find ourselves alone, bereft of our illusions, terrified and paralyzed before God. (ibid)

But the shofar is also a prayer.

Rav Soloveitchik taught of two different types of prayer: the articulated prayer and the un-articulated prayer. The music of the shofar is the un-articulated prayer. Some things can’t be expressed in words. Maybe I don’t know what to say or how to say it. The shofar’s song, like a child crying, is the most basic expression of need; beyond articulation.

My wife and I are blessed with three beautiful children. Sometimes my three year old cries when he wants something. Sometimes he cries because he wants me. When we blow the shofar on Yom Hadin we are calling out to our Father in Heaven, our Avinu Shebashomayim. We are saying, ‘Tateh, Father, I don’t know what I need. But I know I need You!’

After we blow the shofar, the chazzan and congregation recite three verses from psalm eighty nine responsively. We begin, “Fortunate is the people who knows the teruah…”
We don’t just hear or listen, we know. It is an intimate and deep understanding.

The call of the shofar is something beyond words. It speaks to us in a deep way and at the same time expresses what we cannot verbalize.