What is "Eglah Yefefiyah"?
Rashi citing Targum Yonasan: A beautiful kingdom.
Radak: Yefefiyah is two words that mean one matter. The same applies to "Pekach Ko'ach" (Yeshayah 61:1 - release the incarceration), "ha'Buz li'G'ei Yonim" (Tehilim 123:4; the haughty afflicters), "Hu Yenahagenu Al Mus" (Tehilim 48:15 - until death). Here, the last two letters of the root are repeated due to the great beauty. Egypt is compared to a beautiful calf, due to its great beauty and fertility. Also beautiful fertile women are called "Paros ha'Bashan" (Amos 4:11).
Malbim: Egypt honored and esteemed the ox 1 ; they attributed divinity to it. It stood in Nof. When Nof was destroyed, the Bavliyim killed (destroyed) their god. The verse metaphorically calls Egypt a beautiful calf - the calf that they served, they chose a very beautiful calf.
What is his source? We find that they worshipped Tzon (sheep and goats) - "So'avas Mitzrayim Kol Ro'e Tzon" (Bereishis 46:34)! This is why Korban Pesach had to be a lamb or kid! (PF)
What is "Keretz"?
Targum Yonasan: Nations of killers. Rashi - Keretz is an expression of cutting, like "mi'Chomer Koratzti" (Iyov 33:6).
Malbim: It is cutting and slaughter.
Why does it say "from the north"?
Rashi: It is from Bavel.
