THE MONTH of Elul Has Arrived: It Is Time to Awaken | Rabbi Benayahu Shmueli, Head of the Yeshiva
Therefore, anyone who has sense can now change the whole situation. As the Aderet Eliyahu writes—Rabbi Yosef Chaim writes: He says these 51 Awesome Days, from Rosh Chodesh Elul until Simchat Torah, are a sign and an aid for the entire year. If a person guards them, he will overcome his evil inclination, he will overcome his impulse. And if not—woe to him! May he not be caught in the net of the evil inclination.

The month of Elul—what is it? They say that even the fish in the sea would tremble. In truth, the month of Elul is a gift unlike any other in the world.
We should purify ourselves and walk in the path of Hashem. Therefore, we must utilize these days, not pass them in vanity and futility. Wake up, to our Father in Heaven!
Rosh Chodesh Elul is 30 days. After that, there are ten days [until Yom Kippur], and then another ten until the day of Shemini Atzeret—this is called a total of 51 days.
"Please (in Hebrew, נא, the Gematria of 51) save us! Please, Hashem, save us; please grant success." These are days of forgiveness and atonement.
Now is the time. Sometimes a person doesn't know... We see everyone sitting as usual and everything, but many people who were with us as usual—young, old—suddenly gone, without notice.
Therefore, anyone who has sense can now change the whole situation. As the Aderet Eliyahu writes—Rabbi Yosef Chaim writes: He says these 51 Awesome Days, from Rosh Chodesh Elul until Simchat Torah, are a sign and an aid for the entire year. If a person guards them, he will overcome his evil inclination, he will overcome his impulse. And if not—woe to him! May he not be caught in the net of the evil inclination.