en_tn/1sa/24/21.md

you will not cut off my descendants after me

"you will not kill my sons and their families." It was common for a new king who was not from the previous family line to kill off all the children of the former king to prevent any of them from challenging him for the throne.

you will not destroy my name out of my father's house

It is important for each family in Israel to have descendants from generation to generation carrying on the family name and land inheritance. AT: "you will not destroy my family and descendants" or "you will allow my family to live" (See: rc://en/ta/man/translate/figs-metonymy)