Here "Jacob" refers to the descendants of Jacob. AT: "Yahweh will have mercy on the descendants of Jacob" (See: [[rc://en/ta/man/translate/figs-metonymy]])
# attach themselves to the house of Jacob
The house of Jacob refers to the descendants of Jacob, the Israelites. AT: "unite with the descendants of Jacob" (See: [[rc://en/ta/man/translate/figs-metonymy]])