A knife - Rather, “the” “knife”. The single household implement used, not like our knives at our meals, but for slaughtering and cutting up the animals into joints for eating Genesis 22:6, Genesis 22:10; Proverbs 30:14.
Together with her bones ... - Rather, “into her bones”, or “bone by bone, into twelve pieces”. The “pieces” are synonymous with the “bones” (compare Ezekiel 24:4-5). There is something truly terrible in the stern ferocity of grief and indignation which dictated this desperate effort to arouse his countrymen to avenge his wrong. Compare 1 Samuel 11:7.