Why is there an extra 'Yud' in the word "ha'Ivriyim"?
Rashi (Yashan): It is a hint to the ten Makos.
Why did Hashem tell Moshe to ask for only three days' respite?
Ohr ha'Chayim #1, Moshav Zekenim (to 5:3), Hadar Zekenim (to 5:3), Riva (to 5:3): Because Hashem wanted Yisrael to go out with a great possession (to empty out Egypt). In order to achieve this, they had to use the pretext of borrowing their vessels (see 3:22), which was only possible if they were officially going out with the intention of returning. 1
Ohr ha'Chayim #2: Because Hashem wanted to lure the Egyptians down to the Yam-Suf in order to drown them there, and they only fell into the trap because Yisrael 'broke their promise' - that they would return. 2
Oznayim la'Torah #1: Once Yisrael went out for three days and accepted the yoke of Hashem, they would automatically not need to continue to be slaves to Pharaoh, as the Mishnah says (Avos 3:5) - 'Whoever accepts upon himself the yoke of Torah, the yoke of Malchus is removed from him.'
Oznayim la'Torah #2 (to 5:3): To highlight Pharaoh's Rish'us (that, after two hundred and ten years of slavery, he wouldn't free Yisrael even just for three days), so that they would have anything to say in his defense.
Oznayim la'Torah #3 (to 5:3): Initially, Pharaoh invited Yaakov and his family to sojourn (temporarily) in Egypt, and later, he did not allow them to leave - in order to turn them into permanent slaves. So Midah k'Neged Midah, Moshe asked permission to leave temporarily, and used that as an excuse to go out to freedom, permanently.
Why did Hashem see fit to trick Pharaoh? Why did he not simply drown the Egyptians in the Nile, or force them to go down to the Yam-Suf against their will?
Ohr ha'Chayim: Since Pharaoh forced Yisrael into slavery by means of a trick, 1 Hashem responded Midah k'Neged Midah - first Yisrael borrowed their Kelim, and in the end, Hashem drowned them. 2
Refer to 1:11:1.1:2, and 1:13:1:3 and their notes; also refer to 5:21:1:2.
The Vilna Gaon gives a similar explanation.
Why were Yisrael automatically bound to listen to Moshe?
Rashi, Ramban, Targum Yonasan (to Bereishis 50:25): They had a tradition from Yaakov and from Yosef, that they will be redeemed 1 with the expression 'Pakod Yifkod.'
Targum Yonasan (loc. cit.): By two redeemers - Moshe and Aharon.
QUESTIONS ON RASHI
Rashi writes: "'Nikrah Aleinu' - An expression of 'Mikreh,' happenstance, as in, 'va'Yikar [Elokim El Bil'am]' (Bamidbar 23:4) ...." Mizrachi asks - But there, Rashi interprets it as "a disparaging expression of Keri and Tum'ah" (see Rashi loc. cit., and Rashi to Vayikra 1:1)?
Gur Aryeh #1: That is exactly what they were to say before Pharaoh! 'Hashem happened upon us' here in this impure land of Egypt, which is full of idols! That is why "we need to go a three-days' journey into the desert...."
Gur Aryeh #2: In Bamidbar 23:4, Hashem is narrating the Torah, and had He wished to address Bil'am with a term of endearment, 1 He would have written so. But here, the Navi is speaking, and it would be unseemly to ascribe endearment before Hashem to oneself.
Gur Aryeh #3: Bil'am was a Navi, and it is therefore striking that a term of endearment is not used; that is why the word 'va'Yikar' is interpreted disparagingly. Here, the elders that would be present were not necessarily Nevi'im! To say that Hashem "happened" upon them would in fact be appropriate.
Such as 'va'Yikra' spelled with an Alef.
Rashi writes: "They will accept your words - ... once you say this expression [Pakod Pakadti]; for they have a tradition from Yaakov and Yosef that they will be redeemed with this expression." How would they know that Moshe was genuine, just because he would say "Pakod Pakadti"? Perhaps he said it because he knew about the tradition?
Ramban #1 It was a tradition handed down from Yaakov to Yosef, that the first person to use this expression would be the true redeemer, no matter what. 1
Ramban #2 (citing a Midrash): Moshe was a mere twelve years old when he was forced to leave home, 2 so he could not have known of the tradition that Yosef had handed down to Levi, 3 Levi to Kehas, and Kehas to Amram.
Gur Aryeh: When the redeemer would speak these terms, Bnei Yisrael would listen and consider his words (rather than dismissing them out of hand). 4 He would still need to perform the signs to prove his role as redeemer.
Maharal (Gevuros Hashem Ch. 26, p. 108): Hashem promised that when the [true] redeemer would use this phrase, Hashem would strengthen their Emunah, 5 and they would believe his message fully.
Hadar Zekenim: Yaakov did not say 'Pakod,' rather, "v'Heshiv" (Bereishis 48:21)! Moshav Zekenim, Riva - The Torah records that Yosef said so twice. Once he said what Yaakov told him, and once he said so on his own. Also refer 3:18:5.1:1; and to Bereishis 47:30:152:2, and Bereishis 50:1:151:2.
Ramban: Precisely in order that he should not know the secret, because had he remained at home, they would not have believed him.
With instructions that it should remain a secret.
Gur Aryeh: Moshe was torn away from his father's home at a young age (see Ramban in answer #2 (3:18:5:2)); for otherwise, people might claim that Moshe learned the key phrase from his father, and they would indeed dismiss him out of hand. Also refer to 4:1:2:5.
Gur Aryeh: Ramban's approach is that Hashem promised Bnei Yisrael that only the redeemer would use this expression, and no one else (see answer #1 (3:18:5:1)). Gur Aryeh asks - Any person can use their free choice to deceive others (as in Devarim 18:21)! Here Maharal addresses this point; only should Bnei Yisrael themselves begin to believe, does Hashem promise to strengthen that Emunah - when the redeemer uses this phrase.
Rashi writes: "... They have a tradition from Yaakov and Yosef, that they will be redeemed with this expression." Ramban asks - Bereishis 50:24-25 attributes it to Yosef, but what is the source that it comes from Yaakov?
Gur Aryeh: Yosef was not a Navi; how could Yosef know this, had Yaakov not told it to him? Yosef then transmitted it to his brothers, in his father's name.
Also see Da'as Zekenim to Bereishis 47:30, and Ha'amek Davar to Bereishis 50:1. 1
Refer to Bereishis 47:30:152:2, and Bereishis 50:1:151:2.
Rashi writes: "... They have a tradition... that they will be redeemed with this expression (i.e. 'Pakod Pakadti' - I shall surely take reckoning)." What is its meaning, and how does it herald the Redemption?
Gur Aryeh #1: The term "Pakod" means reckoning, which can come for good or for bad. 1 The redemption would include both good for those who would be worthy, and bad for those who transgressed Hashem's will.
Gur Aryeh #2: The word "Pakod" (Pei- Kuf-Dalet) contains hints to the travails that the Jews endured in Egypt, by counting the 'hidden letters' 2 of the word. 3
Maharal (Gevuros Hashem Ch. 26, p. 108): Whereas 'to look,' for example, is the same act whether it is interpreted for good or for bad, to 'take reckoning' of someone for good or for bad is two completely different things.
In the name of the letter Pei (spelled Pei-Alef), only the Alef is hidden; this alludes to the one harshest final year of the exile, when Pharaoh went so far as to slaughter their children. Kuf (Kuf-Vav-Fei) has a hidden value of 86, for the 86 years (since Miriam's birth) that the Egyptians embittered their lives. The hidden value of Dalet (Dalet-Lamed-Sav) is 430, the years that we were strangers (since the Bris Bein ha'Besarim).
Maharal (Gevuros Hashem Ch. 26, p. 108): Thus, there was an 'open' reckoning for the totality of what the Egyptians had perpetrated; as well as a 'hidden' reckoning for every little detail of what they did.
Rashi writes: "... They have a tradition... that they will be redeemed with this expression (Pakod Pakadti)." Why is the word doubled?
Gur Aryeh #1: The redemption would entail a dual reckoning - of good for Yisrael, and evil upon the Egyptians. 1
Maharal (Gevuros Hashem Ch. 30, p. 116): The process of the redemption itself would be divided in two. (After Moshe requested their release, Pharaoh intensified their labor, and Moshe faded from view for six months! Only then did the ten plagues begin.)
Gur Aryeh #2: The double Pei reminds us that the letter comes in two forms - bent, and straight (Pei Sofis). According to Pirkei d'Rebbi Eliezer (48), the 5 ending letters allude to salvation. 2 Specifically, the letter Pei Sofis alludes to the redemption from Egypt.
Maharal (loc. cit. Ch. 26, p. 108): It is thus a more exalted Midah; refer to 3:18:5.2:1 and its note.
Gur Aryeh: Hashem created the world with the 22 letters of Alef-Beis. The five final letters are even greater; Hashem uses them to create the Geulah. They have a higher numerical value (Gematriya); they complete a word, and nothing may follow them. Also see Maharal (Gevuros Hashem Ch. 26, p. 109) - "With these five letters, Hashem engraved the world's redemption." He explains why these letters are on a higher level, and why there are specifically five of them.