Seeing as the tone of the Parshah is Midas ha'Din, why does the Torah write "Vayomer Hashem" (and not 'Vayomer Elokim')?
Ramban: It was a sign that Hashem would save Yisrael with His Midas Rachamim.
What is the significance of the statement "Ki Yada'ti es Mach'ovav"? Wasn't that obvious?
Rashi: Of course Hashem knew! What He meant was He would now take it to heart, and would no longer close His eyes and stop up His ears to their suffering and cries. 1
Seforno: It means that, no matter what, He has seen and will act. 2
How did Hashem's words answer Moshe's question (Refer to 3:4:1:1)?
Seforno: Hashem told Moshe that the objective of the plagues would be to rescue Yisrael from the Egyptian's hands, and bring them to Eretz Cana'an, and not to settle them in Egypt. 1
As He will clarify in the next Pasuk (Seforno). Consequently, it was basically unnecessary to annihilate the Egyptians.
Why does the Torah sometimes call a lamb Kesev, and sometimes Keves?
Refer to Bereishis 39:40:151:1 and the note there.
Rashi writes that the Torah teaches a lamb and a goat separately, because they differ about the tail. It should teach a goat with cattle. There is no difference between them!
Moshav Zekenim: Cattle are not like goats at all. However, sheep and goats were taught together regarding Olah. Also here they would be taught together if they did not differ about the tail.
Why does it say "Im Kesev Hu Makriv"?
Moshav Zekenim (citing Sifra): Im Kesev includes the tail of a lamb of Korban Pesach. V'Im Kesev 1 includes a Pesach whose year passed, or Shelamim brought due to Pesach 2 for all Mitzvos of Shelamim - Semichah, Nechasim and Tenufah of Chazah v'Shok. However, it is eaten only for one day and a night, like the law of what it was initially Hukdash for. Ben Azai says, it is eaten only at night, and roasted, like Pesach.
Moshav Zekenim: The Sifra expounds Im, and the the prefix Vov. This is unlike Rashi, who says that "Kesev" is extra, for Tzon is sheep and goats, and the next Pesach discusses goats. (In our texts, there is no prefix Vov, and Sifra expounds Kesev and Im Kesev, like Rashi - PF.)
Moshav Zekenim: This is Mosar Pesach, i.e. Temuras Pesach, or it was lost and the owner offered another in place of it. It is not the Chagigah of Erev Pesach (to be satiated from eating it before eating Pesach. Rashi (Pesachim 96b) brings both Perushim.)
למה נכפל "ראה ראיתי"?
מהר"ל, גבורות ה' (פכ"ד עמ' ק"ג ד"ה ויאמר): דרשו מכאן- ראיתי שבאים לסיני וראיתי מעשה עגל, והכוונה שישראל אינם נגאלים על תנאי שהם צדיקים, אלא גם אם יחטאו- יקראו אל ה' ויֵענוּ.
מה הם הדברים המפורטים כאן שבזכותם נגאלו?
מהר"ל, גבורות ה' (סוף פכ"א עמ' צ"ד): בחסדי אבות [ככתוב בפסוק הקודם, וזה מידת החסד], במידת הדין (- "ראיתי את עֹני עמי" בגלל העול שעשו להם), בתפילה (-"צעקתם שמעתי"), ובמידת הרחמים (- "כי ידעתי", והאוהב והמודע נקרא 'רחמוהי'). עיי"ש. 1
למה נזכרו כאן 3 דברים- "ראיתי...שמעתי...ידעתי"?
מהר"ל, גבורות ה' (פכ"ד עמ' ק"ג ד"ה ויאמר): הראיה היא הראשונית, לאחריה השמיעה שיש בה קבלה, ויתירה ממנה הידיעה- שהוא יודע את הדבר כאשר הוא [על אמתתו].