(1) ליל שמרים IT WAS NIGHT OF WATCHING [UNTO THE LORD] — a night which the Holy One, blessed be He, was watching for and looking forward to, that He might fulfill His promise להוציאם מארץ מצרים TO BRING THEM OUT FROM THE LAND OF EGYPT. (2) 'הוא הלילה הזה לה IT IS THIS NIGHT OF THE LORD — it is the night of which He said to Abraham, “On this night will I redeem your children” (Mekhilta d'Rabbi Yishmael 12:42; cf. Rashi on Genesis 39:11). (3) שמרים לכל בני ישראל לדרתם [IT IS A NIGHT] OF PROTECTION FOR ALL THE CHILDREN OF ISRAEL THROUGHOUT THEIR GENERATIONS — this night is protected, and comes as such from ages past, against all destructive forces, as it is said, (v. 33) “And He will not permit the destroyer [to enter your houses]” (Pesachim 109b; Rosh Hashanah 11b).
Rav Naḥman said that the verse said: “It was a night of watching to the Lord” (Exodus 12:42), which indicates that Passover night is a night that remains guarded from demons and harmful spirits of all kinds. Therefore, there is no cause for concern about this form of danger on this particular night.
ר' יהושע אומר בניסן נגאלו בניסן עתידין ליגאל מנלן אמר קרא (שמות יב, מב) ליל שמורים ליל המשומר ובא מששת ימי בראשית
Rosh Hashanah 11b:4
It was also taught in the baraita: Rabbi Yehoshua says: In Nisan our forefathers were redeemed from Egypt; and in Nisan in the future the Jewish people will be redeemed in the final redemption. The Gemara asks: From where do we derive that the final redemption will be in Nisan? The verse states: “It is a night of watching for the Lord for bringing them out from the land of Egypt; this is the Lord’s night of watching, for all the children of Israel throughout their generations” (Exodus 12:42). This teaches that the night of Passover is a night that has been continuously watched, i.e., set aside for the purpose of redemption, from the six days of Creation, and it will continue to be so until the final redemption.
מ
ליל שימורים הוא לה', G’d had been anticipating this night ever since the days of the patriarchs in order to have the opportunity to lead the Jewish people out of Egypt. For the Jewish people, on the other hand, this night now became a night to be remembered.
Rashbam on Exodus 12:42:3
שמורים, represents an element of “waiting for something.” It is used in this sense in Genesis 37,11 ואביו שמר את הדבר, “his father waited to see what would happen in this matter.”
ספורנו על שמות י״ב:מ״ב:ב׳
הוא הלילה הזה לה' שמורים וכמו שהיה משמר ומצפה לגאולת ישראל כל ימי גלותם במצרים, כן הוא משמר ומצפה לגאולת ישראל העתידה, כאמרו ולכן יחכה ה' לחננכם:
Siftei Chakhamim, Exodus 12:42:1
It is continuously protected from destructive forces. Rashi is answering the question: What does “this night remains a vigil for all generations” mean? Surely, this actual night of the Exodus does not remain forever. Rashi answers: “It is continuously protected.” I.e., every year when this night comes, it is protected from destructive forces.
Haamek Davar on Exodus 12:42:1
A vigil (or “Stored up”) … for all the B’nei Yisrael. Because this was the time of Yisrael’s first redemption it was “stored up” for them for all generations as an auspicious time for deliverance from every type of affliction.
ליל שמורים, “a night of fulfillment of anticipations.”
1)According to Ibn Ezra, G’d stood watch during that night and did not allow the destructive force to enter the homes of the Jews. This is why He commanded that in future the beneficiaries of His standing watch, i.e. His people, should observe that night by observing a special watch. This is the appropriate manner of thanking the Lord and praising Him for what He did for us.
2)Nachmanides...interprets the word שמורים as a reference to the conclusion of a watch over the fate of the Jewish people from the time when the covenant between the pieces was concluded with Avraham 430 years earlier. It is also possible to understand the word ליל שמורים as summing up all the strenuous efforts G’d had had to make in order to ensure that by that night the Jewish people would be on a spiritual level that would justify their redemption for all time.
3)Sforno on Exodus 12:42:2
הוא הלילה הזה לה' שמורים, just as G’d had looked for ways and means to bring the redemption to the Jewish people from their suffering in Egypt, so He is looking for legal ways and means to redeem us from the present exile and to bring on the final redemption. Isaiah phrased this asולכן יחכה ה' לחננכם, “Truly, the Lord is waiting to show you grace.” (Isaiah 3018)
That was for the LORD a night of vigil to bring them out of the land of Egypt; that same night is the LORD’s, one of vigil for all the children of Israel throughout the ages. It says in the Midrash that in this world, G-d performs miracles in the night if they are passing miracles, but miracles that are continuous are done in the day. And as illustrated in this parsha, the Galut is analogous to night, which is to say that if the redemption happens at night it is still a time of Galut (while a redemption occurring during the day its a sign that the Galut and the night truly ended). Yetziat Mitzraim (the redemption from Egypt) was only the middle of process, and a preparation for the future redemption.