The month of Nisan is an exceptional time.
The Avnei Nezer zt’l (Avnei Nezer, Orach Chaim 336) writes in a letter, “I received your letter Erev Shabbos close to Shabbos. You asked that I answer some of your questions regarding the yom tov Pesach. You asked a difficult request because these are priceless days — each hour is like a day.... Nevertheless, since you expressed your strong desire that I answer you and wrote that it will be your pleasure and simchas yom tov, I dedicated some time to write this letter...”
The Shem MiShmuel zt’l said that his father, the Avnei Nezer, would be והולך מסובב העליונים בעולמות, “Walked in the upper worlds” throughout Nisan (Avir HaRo’im 264). Once, the Shem MiShmuel heard his father say that during Nisan he doesn’t need to sleep due to the holiness of these days (Avir HaRo’im 299).
Shulchan Aruch (429:2) states, "We don’t say tachanun the entire month of Nisan." The Shlah Hakadosh (Pesachim, Ner Mitzvah, 7) explains that this is because the entire month has the kedushah of Rosh chodesh. He writes, "It states, חדשים ראש לכם הזה החודש, 'This month is for you Rosh chodesh.' This means each day of Nisan is like חדש ראש. The entire month is Rosh chodesh."
The Agra d’Kala (Pekudei) teaches in the name of Rebbe Mendel of Riminov zt'l that the first twelve days of Nisan represent the twelve months of the year, and tzaddikim can perceive on these days what will occur in the world in the corresponding months. "The Chozeh of Lublin zt'l would write down what he perceived with his ruach hakodesh would happen that year. On ניסן 'א he wrote what would happen in Nisan. ניסן 'ב he wrote what would happen in Iyar, and so on. When it was the final year of his life, he only wrote down what would occur up to Av. He didn't write what would happen in the world in the following months because he was niftar in Av that year. This story is known among the Chozeh's students."
Once, at the start of Nisan, the directors of Satmar institutions came to the Satmar Rebbe zt'l to discuss the institutions’ finances. The Satmar Rebbe asked them to return after Pesach. He explained, "Reb Yehoshua of Kroli zt'l said if one doesn’t attain ruach hakadosh at the Seder, he isn't a human being. So, we must prepare. Therefore, I prefer to discuss financial issues after Pesach."
The Avodas Yisrael zt'l (Shabbos HaGadol, ה"ד בגמרא) writes, "By all other holidays [Succos, Shavuos, and so on], the holiness of the yom tov arrives gradually. Each tefillah ushers in another aspect of the holiday. But Pesach, the kedushah of the yom tov comes at once. It is called פסח, which means to jump [because it doesn't come in gradually, step by step. One jumps right into the peak of the kedushah of the yom tov]. So, Pesach needs preparation. A bright spiritual light will come down to us regardless of our deeds, but one needs to be pure to receive this bright light. It can be compared to the sun that shines brightly, but its rays can't enter one's home if the window shades are closed..."
So, it is a time to prepare, to live with holiness and purity, so that when the great light of Pesach shines, we will be able to receive it.
There are many ways to prepare for Pesach. For example, you can daven for a good yom tov, yearn for it, learn about the mitzvos, etc. Furthermore, every good deed you do that adds to your kedushah and taharah (such as learning a daf Gemara and so on) can be intended as a preparation for the upcoming mitzvah.
Furthermore, every preparation for Pesach is a great preparation. The Kav HaYashar (90) writes, “I received a kabbalah that every effort that one invests in honor of Pesach, and he becomes tired and exhausted from that work, it kills all the mazikim that are called אדם בני נגעי. When one works for Pesach, this rectifies [severe sins]. The heart knows the bitter truth that almost none of us are clean from that [severe] sin. Therefore, everyone is obligated to fix whatever he can, and Hashem, with His immense mercy and kindness, will accept the thoughts of the Jewish people, His nation, and will redeem us quickly.”
It is known that after Yom Kippur passes, we remain clean from aveiros for four days. The Shlah Hakodesh explains that this is because people are preparing for the Yom Tov of Succos, choosing the four minim and building a succah, and they do so with emotion and joy. This purifies them, and the taharah of Yom Kippur remains. The Chidushei HaRim zt’l says that the same happens each year before Pesach. Everyone is cleaning, searching, and burning the chametz. When we come to the Seder, we’re entirely clean from aveiros and fitting to receive the holiness of the yom tov.
Rebbe Levi Yitzchok of Berdichev zy’a said, "By cleaning for Pesach, one should be able to attain ruach hakadosh; only anger ruins it."
Chazal (Shabbos 105) say, עובד כאילו הכועס כל זרה עבודה, "Whoever becomes angry, it is as though he worshiped idols." Why is anger compared to idol worship? We can explain that it’s because neither accomplish anything. One doesn’t gain anything from idol worship, as we say in Hallel: ...ידברו ולא להם פה, "They have a mouth, but they can't speak..." Anger is also futile, as Chazal (Kiddushin 41.) say, “Whoever becomes angry, all that he has is anger.” Nothing else was accomplished.
Rebbe Asher of Stolin zt'l explained that this is the reason the pasuk puts together the mitzvah of Pesach with avodah zarah, as it states (Shemos 34:17-18) חג את לך תעשה לא מסכה אלהי תשמר המצות, "Don’t make molten gods for yourself. Keep the holiday Pesach..." What is the connection between avodah zarah and Pesach? When people prepare for Pesach, they are often liable to become angry, and the passuk warns us to be cautious. And when we clean for Pesach and are careful to avoid anger, this is an excellent preparation for the approaching yom tov.
