RobH_en_tn/1ki/02/33.md

may their blood return on the head of Joab and on the head of his descendants

The word "blood" is a metonym for murder. And, the idiom "blood return on the head of" means the person should be considered guilty for murder. Alternate translation: "I want Yahweh to hold Joab and his descendants guilty" (See: rc://en/ta/man/translate/figs-metonymy and rc://en/ta/man/translate/figs-idiom)

to his house, and to his throne

The words "house" and "throne" are metonyms for the family and the kingdom. Alternate translation: "to David's descendants and to David's kingdom" (See: rc://en/ta/man/translate/figs-metonymy)