John Calvin Commentary Isaiah 9:20

"And one shall snatch on the right hand, and be hungry; and he shall eat on the left hand, and they shall not be satisfied: they shall eat every man the flesh of his own arm:" — Isaiah 9:20 (ASV)

Every one shall snatch on the right hand. It is equivalent to a phrase in common use, prendre et ravir a toutes mains, to take and seize at all hands. This mode of expression denotes either insatiable covetousness or insatiable cruelty, for the eagerness to snatch incites to savage cruelty.

He expresses more emphatically that they will be insatiable by saying that, because they are impelled by blind fierceness and inconceivable rage, they will suck their brother’s blood as freely as they would devour the flesh that was their own property. The bitterness of the vengeance is greatly heightened by this circumstance: that the children of Abraham, and the holy posterity of the chosen race, break out into such beastly fury.

Let us therefore remember that it is a dreadful proof of heavenly punishment when brothers are driven, with irreconcilable eagerness, to inflict mutual wounds.