en_tn_lite_do_not_use/oba/01/18.md

house of Jacob will be a fire ... Joseph a flame

Yahweh speaks of the houses of Jacob and Joseph as if they were fire because they will destroy Esau like a fire that quickly and completely burns up straw. (See: rc://en/ta/man/jit/figs-metaphor)

stubble

The dry pieces of plants that are left in the ground after the stalks have been cut.

and they

The word "they" refers to the house of Jacob and the house of Joseph.

will burn them

The word "them" refers to the descendants of Esau, who are the nation of Edom.

There will be no survivors to the house of Esau

"Not one person of the house of Esau will survive"

the house of Esau

The word "house" is a metonym for the family that lives in the house. In this case it refers to Esau's descendants. Alternate translation: "descendants of Esau" (See: rc://en/ta/man/jit/figs-metonymy)

for Yahweh has spoken it

This is an oath formula that means it will certainly happen because Yahweh said it.