The rest of the people of Bethulia fell upon the Assyrian camp: The rest of the people would be the women, children, and old men who were not out pursuing the enemy. Fell upon means that they “violently entered” the camp of their enemies. With no danger to themselves they could loot at will. This is in marked contrast to the book of Esther, where the Jews kill their enemies, but refrain from looting (Est 9.10, 15-16).

Plundered means that they “took [or, carried off] the possessions” of the Assyrians.

And were greatly enriched may be rendered “became very rich” (similarly Good News Translation).

Quoted with permission from Bullard, Roger A. and Hatton, Howard A. A Handbook on Judith. (UBS Helps for Translators). New York: UBS, 2001. For this and other handbooks for translators see here.