The sons
ben (bane)
a son (as a builder of the family name), in the widest sense (of literal and figurative relationship, including grandson, subject, nation, quality or condition, etc.
of Jacob
Ya`aqob (yah-ak-obe')
heel-catcher (i.e. supplanter); Jaakob, the Israelitish patriarch -- Jacob.
came
bow' (bo)
to go or come (in a wide variety of applications)
upon the slain
chalal (khaw-lawl')
pierced (especially to death); figuratively, polluted -- kill, profane, slain (man), slew, (deadly) wounded.
and spoiled
bazaz (baw-zaz')
to plunder -- catch, gather, (take) for a prey, rob(-ber), spoil, take (away, spoil), utterly.
the city
`iyr (eer)
or (in the plural) par {awr}; or ayar (Judges 10:4) {aw-yar'}; a city (a place guarded by waking or a watch) in the widest sense (even of a mere encampment or post) -- Ai (from margin), city, court (from margin), town.
because they had defiled
tame' (taw-may')
to be foul, especially in a ceremial or moral sense (contaminated) -- defile (self), pollute (self), be (make, make self, pronounce) unclean, utterly.
their sister
'achowth (aw-khoth')
a sister (used very widely, literally and figuratively) -- (an-)other, sister, together.