This simile means that even after Yahweh destroys Israel, he will still set apart people from among the Israelites to serve him. (See: [[rc://en/ta/man/translate/figs-simile]])
The people who will serve Yahweh after armies destroy Israel are spoken of as if they were set apart as a holy seed. (See: [[rc://en/ta/man/translate/figs-metaphor]])