This introduces a new event in the story of the struggle between David's supporters and Saul's family. (See: [[rc://en/ta/man/translate/writing-newevent]])
This refers to Saul's family and supporters who assumed control of his estate after he died.
# house of David
This refers to the supporters of David.
# Abner made himself strong in the house of Saul
Abner's increasing power over Saul's family is spoken of as if he became physically stronger. AT: "Abner gained more power over the family and supporters of Saul" (See: [[rc://en/ta/man/translate/figs-metaphor]])