Why does it say "v'Sichsachti [Egypt b'Egypt]"?
Rashi: The continuation of the verse explains this - "a man will fight with his brother."
Radak: I will confound. This is like "v'Es Oyvav Yesachsech" (9:10). He will befuddle them among themselves, aside from the enemy that will come against them. "A man will fight with his brother, and a Mamlachah with a Mamlachah", even though Egypt is all one kingdom, there were nobles under the great king. This one rules in this province, and this one rules in this province, like the kings of Kena'an.
Malbim: The verse depicts that the Navi heard Hashem say so on his way to Egypt. It says "Ne'um ha'Adon Hashem Tzevakos" (4). "I will besiege the country of Egypt via the Egyptians themselves" - some Egyptians will afflict others; a man's sword will be against his colleague.
What is the significance that "a man will fight with his brother, a man with his fellow man"?
Malbim: Normally, when one kingdom fights another, all the cities under one kingdom make peace with each other, and they are united with one heart to fight those who stand against them. Similarly, when one city fights another, all the people of one city make peace with each other, to be like one person against the city that fights it. When one family fights another, a man with his colleague, all the brothers and relatives in that family join together. However, here initially "a man will fight with his brother" - there will be discord between brothers, and afterwards "a man will fight with his fellow man" - family against family, "city against a city, kingdom against a kingdom." There will be interior and exterior wars!
