What is the definition of "Tzefarde'im"?
Rashi, Ramban #1, Rashbam, Targum Onkelos and Targum Yonasan: Frogs.
Ramban #2 (to 10:14, citing R. Chananel) and Seforno (to 8:11): Crocodiles.
Why does it say "Kol Gevulecha"?
Shemos Rabah (10:2): Egypt and Kush had a feud about where the border between them was. 1 The frogs went until the end of Egypt's border. This clarified the border, and made peace between them.
Also the verse, "Eretz Mitzrayim... v'Ad Gevul Kush" (Yechezkel 29:10) shows that they border each other. How can the Gichon river surround Kush (Bereishis 2:13)? It has the same source as the Chidekel (which goes east of Ashur) and Pras (Euphrates) rivers, in Asia (ibid., 2:10, 14)! R. David Kahn (Yated Ne'eman 5771 29, Mosaf Shabbos p.4-5) brings that there is a place called Kush near India and Shushan, aside from the Kush in Africa. (He resolved other difficulties via this approach as well. - PF)
QUESTIONS ON RASHI
Rashi writes: "Im Ma'en Atah - If you are a Sarvan (a stubborn refuser)...." What needed grammatical clarification here?
Gur Aryeh: Do not read "Ma'en" as a past-tense verb (as was the word "Mei'ein" in 7:14). That verb was in third-person; whereas our verse (with the word "Atah") is clearly in second-person. Rather, "Ma'en" is an adjective, or title - 'a refuser.'