“And when you will gather the nation you shall blow the tekiah (straight sound) and not the teruah (broken sound).”
Why does the possuk add the words “and not the teruah?” If the Torah explicitly says to blow the straight sound, it is understood that the teruah shall not be blown at the gathering.

The verse hints at an important message, which comes to light with the following story:

When the renowned Rabbi Shlomo of Munkacz, author of Shem Shlomo, was a young chosson, he traveled with his father, the saintly Rabbi Eliezer of Lanzut, to the tzaddik Reb Meir’l of Premishlan. Reb Meir asked the young man what he received as a gift from his future father-in-law, to which Rabbi Shlomo replied that he received a watch.

“A watch teaches us the same lesson as the tekios (the shofar blowing on Rosh Hashana),” said Reb Meir’l. “A watch is designed to run with precision and show the exact time. What happens when it breaks down? The person takes his watch to the watchmaker, who unscrews the small instrument and takes apart the miniscule pieces. After he dissects it completely, he puts it back again so that it should work properly.

“The same is true about a person,” continued Reb Meir’l. “‘Hashem created the person to be just’ – Hashem created us to do mitzvahs and stay away from sin. What happens if a person ‘breaks down’ and commits aveiros? Then he has to do tshuva and break his heart with sincere regret. After taking his heart apart like a watchmaker who is repairing a watch, he will become straight again.

“This is what the shofar is telling us,” Reb Meir’l concluded. “The tekiah is a straight sound to remind us that we were created to be just. Shevarim is three short sounds, resembling the sins that break up our righteousness. So what are we to do? The answer is in the third sound of the shofar, the teruah, which is a broken sound. The teruah is telling us to break our hearts with regret and repentance. The final sound is once again the tekiah – the straight sound, indicating that after proper tshuva we become complete again.”

Reb Meir’l then turned from the young chosson to his great father, Reb Eliezer, and said: “What I said before was for the young man. But for you, a leader who gathers the Jewish people, there is a different message in the Torah: ‘tiski v’lo terui - the straight sound but not the broken sound!’ A leader must be strong! A leader may not become broken and easily swayed. Otherwise, the people will tell him what to do instead of listening to him.”

With this story, we can understand why the verse emphasizes not to blow the teruah – the broken sound, when the Jewish people are being gathered.