Isaiah 9:21

“Manasseh, Ephraim; and Ephraim, Manasseh, &c.] That is, “Manasseh” shall eat or devour “Ephraim”; and “Ephraim” shall eat or devour “Manasseh”; as the Septuagint, Syriac, and Arabic versions render it; which is to be understood of their quarrels, contentions, and wars among themselves, whereby they bit, devoured, and consumed each other, though they were brethren; which explains and confirms what is before said, of no man sparing his brother, and everyone eating the flesh of his own arm. The Targum paraphrases the words thus, “they of the house of “Manasseh”, with those of the house of “Ephraim”, and they of the house of “Ephraim”, with those of the house of “Manasseh”, shall be joined…”

“Manasseh, Ephraim--the two sons of Joseph. So closely united as to form between them but one tribe; but now about to be rent into factions, thirsting for each other's blood. Disunited in all things else, but united "together against their brother Judah" (Kg2 15:10, Kg2 15:30). Next: Isaiah Chapter 10”

“Manasseh, Ephraim - This verse is a continuation of the statement in regard to the extent and fearfulness of the faction. Those who were hitherto most tenderly and intimately allied to each other, would now be engaged in furious strife. Manasseh and Ephraim were the two sons of Joseph Genesis 46:20, and their names are used as expressive of tender union and friendship; compare Genesis 48:20. The tribes of Ephraim and Manasseh were near each other, and they always were allied together. The expression here denotes that they who had hitherto been joined in tender alliance, would be rent into contending factions, thirsting for each other’s blood. And they together - They would be united in…”

“Manasseh - Though more near and dear to one another than any other tribe, being both sons of Joseph. Next: Isaiah Chapter 10”

“9:21 Manasseh and Ephraim represent the northern kingdom as its largest tribes. The two largest tribes of Israel and Judah fought amongst themselves. This is probably a reference to the war between Judah and the alliance of Syria and Israel, which is commonly called the Syro-Ephraimite War (7:1-12). In that conflict, brothers savagely fought against brothers (2 Chr 28).”

“Ephraim: Jdg 7:2; Sa1 14:20; Kg2 15:30; Ch2 28:6-8; Mat 24:10; Gal 5:15 For all this: Isa 9:12, Isa 9:17, Isa 5:25, Isa 10:4; Jer 4:8 Next: Isaiah Chapter 10”