What is the significance of "Leil Shimurim Hu La'Hashem"?
Rashi, Ramban #1 and Targum Yonasan 1 : It is the night that Hashem was waiting for, 2 to fulfill His promise to Avraham 3 to redeem his children, to take Yisrael out of Egypt.
Ramban #2 and Hadar Zekenim: It was the night for which Hashem was waiting - for the moment that they would be worthy of redemption.
Rosh Hashanah 11b #1 (citing R. Yehoshua): It is the night that has been under wraps since the six days of Creation, to redeem (Yisrael).
Rosh Hashanah 11b #2 (citing R. Eliezer): It is the night that is guarded against destructive angels (the demons). 4
Maharal: See below, 12:42:1.2.
Targum Yonasan: With reference to the four special nights that are recorded in Hashem's Book of Chronicles - 1. The night on which He revealed Himself to create the world; 2. The night on which He revealed Himself to Avraham (at the Bris Bein ha'Besarim); 3. The night on which He revealed Himself in Egypt, when with His Hand He killed the Egyptian firstborn, while with His right, He saved those of Yisrael; 4. The night on which He will reveal Himself to redeem Yisrael from among the nations (see also Targum Yerushalmi).
Ramban: Since this was the night that He fixed at the Bris Bein ha'Besarim, and He was awaiting its arrival.
Gur Aryeh: We derive that Hashem said to Avraham, 'On this night I shall redeem your children;' otherwise the phrase "it is this very night" would be extra.
Tosafos (loc. cit.): And R. Yehoshua accepts this interpretation as well.
Why does the Torah call it "Leil Shimurim" in the plural?
Oznayim la'Torah: Because many miracles happened specifically on the night of the fifteenth of Nisan, 1 all leading up to the Redemption from Egypt on the same date. 2
See Yotzros for Shabbos ha'Gadol - "Az Rov Nisim Hifleisa ba'Laylah" (also recited in the Hagadah at Nirtzah).
This explains why the Gemara says in Berachos 9a, that redemption actually occurred at nighttime. Refer to 12:42:1:1*.
According to Maharal, why is this night "Leil Shimurim"? What does "Leil Shimurim" mean?
Maharal #1 (Chidushei Agados Vol. 1, p. 99, to Rosh Hashanah 11b): On this night, "No dog whetted its tongue against Bnei Yisrael" (11:7); this hints that the Mazikim were likewise powerless. It was a night of Redemption - from the Mazikim as well. 1 It was at that time that we came under Hashem's domain, 2 when He took us as His own, and redeemed us from others' control. Accordingly, no other force has power over us then. 3
Maharal #2 (ibid. p. 100): It is the night for eating Matzah, which is also "guarded" against becoming Chametz. Mazikim are associated with Chametz and Se'or; 4 whereas Pesach night represents Chesed, 5 the trait of Avraham. 6
Maharal #3 (Gevuros Hashem Ch. 38, p. 142): The first day of Pesach is called "Rishon," 7 and it comes in the first month. Mazikim have control only over the plural, 8 not upon unity. 9
Maharal: That is why at Ma'ariv, the Berachah of "Ga'al Yisrael" is followed by "Hashkiveinu," requesting Divine shelter and protection.
It is a night reserved for Redemption, through miracles and wonders that transcend nature.
Maharal: This sheds light on the Gemara (Berachos 9b), that whoever recites [the blessing of] Geulah immediately before his Tefilah, will not be harmed that entire day.
Which are associated with the left (north) side. For more about the negative associations of Chametz, refer to 12:15:159.
Chesed is associated with the right (south) side. However Maharal elsewhere (see Be'er Ha'Golah, Be'er #2, p. 29) writes that Mazikim relate to the right side as well, just as Zugos (pairs) alternate right and left (also see Nesivos Olam, Nesiv Ha'Avodah Ch. 19, p. 145). See the following answer and its note (12:42:1.2:3***).
Refer to 12:8:2.2:3 - The Mitzvah to eat Matzah corresponds to Avraham; other Mitzvos on this night correspond to the other Avos and Imahos.
Pesachim 5a.
Especially items that come in pairs (Zugos); see Pesachim 113a. But on this night, we are unconcerned about Mazikim, and we drink four cups (ibid. 109b).
Maharal (loc. cit.): Something that exists in its own right is "first," and that which comes along by default is "second." The Mazikim were not created for their own sake, but rather as an outcome of the creation of the world. They therefore have no control over the time called "Rishon - i.e., when the true purpose of Creation is revealed (EK). Maharal (Be'er Ha'Golah, Be'er #2, p. 28) - Keri'as Shema at bedtime serves as protection, because by focusing on Hashem's Unity, one overcomes the Mazikim that represent the plural (also see Maharal, Nesivos Olam, Nesiv Ha'Avodah Ch. 19, p. 144). As explained above, there is no place for Mazikim at the revelation of Hashem's Unity, which is the foundation, as well as the goal, of Creation. (As mentioned above, Maharal (in Be'er Ha'Golah and Nesiv ha'Avodah) places the plural aspect of Mazikim conceptually at both the right and left. We may explain that although Hashem conducts the world in two ways, Chesed and Din, the root of both is Chesed - the desire to bestow good. The divided ways of conducting the world open the door to evil, and to those who oppose Hashem's Will; but the essential Chesed reveals that all is one, towards one purpose. At this level - the Divine Will to bestow good - there is no place for plurality or for Mazikim.) (EK)
What is the significance of the second mention of the term "Shimurim" - "[Leil ...] Shimurim l'Chol Bnei Yisrael, l'Dorosam"?
Rashi: It is the night on which Yisrael are continually 1 protected against destructive angels. 2
Ramban and Hadar Zekenim: It is the night that Hashem waited for to take Yisrael out of Egypt; it is (sanctified) for Hashem for all generations, for them to serve Him by eating the Pesach and remembering the miracles (Hagadah), and by reciting Hallel and giving thanks to His Name. 3
Seforno: It teaches us that just as Hashem waited for the night of the redemption from Egypt, so too, does He wait to redeem them [from the current Galus].
Targum Yonasan: It is the night that is guarded against destructive angels (the demons), and to redeem them from the nations forever.
Hadar Zekenim: Bnei Yisrael also wait for this night, when they can celebrate the Halachos of Pesach.
Mechilta: It is the night on which all of Yisrael need to be guarded (against destructive angels). 4
Oznayim la'Torah: It refers to the numerous miracles that occurred on this night, and those that will occur at the time of the final Ge'ulah. See the Piyut, 'Az Rov Nisim Hifleisa ba'Laylah' in Nirtzah. 5
Gur Aryeh: Rashi comes to explain the term "l'Dorosam." The Pasuk began by discussing the night of the Exodus itself; in what way is it "Shimurim" for all generations? Rather, every time this date arrives, it will serve as protection for Bnei Yisrael.
As the Torah writes later (13:10) and in Devarim (16:1).
To conform to the opinion of R. Yehoshua (Rosh Hashanah 11a), according to whom Mashi'ach will come in Nisan.
The Gemara (Rosh Hashanah 11b) presents two views to explain "Leil Shimurim." According to Rebbi Yehoshua, Hashem reserved this date since Creation as the date of the Redemption; whereas according to Rebbi Eliezer, it is a night of protection from Mazikim. How does each opinion explain our Pasuk as a whole (with both instances of the word "Shimurim")?
Maharal (Gevuros Hashem, beg. Ch. 38, p. 141): To Rebbi Eliezer, the date was reserved, ever since Creation, for the Redemption from Mitzrayim; this is expressed in the protection from Mazikim [which are powerless] on this night. As such, it was fitting to redeem Yisrael from their Mazikim/foes on this night. According to Rebbi Yehoshua, the night in itself is reserved by Hashem for the Redemption - both past and future. 1
According to Rebbi Yehoshua, the future Geulah will take place in Nisan; whereas according to Rebbi Eliezer, it will take place in Tishrei. It emerges that according to R. Yehoshua, "Leil Shimurim" refers primarily to the future; whereas according to R. Eliezer focuses on to the past, ever since Creation.
QUESTIONS ON RASHI
Rashi writes that it is the night that Yisrael is protected against Mazikin. But the Mechilta explains that it is a night that needs guarding?
Moshav Zekenim: The Mechilta means that the Mitzvos of the Seder require guarding. 1
Refer to 12:42:1:4
Moshav Zekenim: As the Torah writes, "u'Shemartem Es ha'Matzos" (12:17); "u'Shemartem Es ha'Davar ha'Zeh" (12:24). But the Mechilta specifically says that it is Yisrael who need guarding.
Rashi writes that it is the night that Yisrael is protected against Mazikin. If so, why do we [begin to] read the Hagadah in Aramaic (which angels do not understand)?
Moshav Zekenim #1: Because the Mazikin cannot enter [our houses to harm us] by themselves, but if [they hear and understand that] we invite 'anyone who needs,' they will accept the invitation.
Moshav Zekenim #2: The reason it is in Aramaic is not due to fear [of Mazikin].
