The phrase "light of Israel" refers to Yahweh. It is unclear whether Yahweh or Isaiah is speaking. AT: "I, Yahweh, the light of Israel, will become like a fire" (See: [[rc://en/ta/man/translate/figs-metaphor]])
"The fire will burn and devour the king of Assyria's thorns and briars." The speaker compares the king of Assyria's army to thorns and briers. This emphasizes how easily God will destroy them. AT: "I will destroy the Assyrians like a fire burning thorns and briers" (See: [[rc://en/ta/man/translate/figs-metaphor]])
The words "briers" and "thorns" both refer to useless, thorny plants; they can be translated using one expression. See how you translated these words in [Isaiah 7:23](../07/23.md). AT: "thorn bushes" (See: [[rc://en/ta/man/translate/figs-doublet]])
Possible meaning are 1) "Yahweh will destroy the great forests and farmlands in the nation of Assyria" or 2) "Yahweh will destroy the army of Assyria as a fire burns up great forests and farmlands." (See: [[rc://en/ta/man/translate/figs-metaphor]])
Possible meanings are 1) this emphasizes that God will completely destroy the forests and farmlands. AT: "completely" or 2) this means God will completely destroy the people of Assyria. The phrase "soul and body" refers to the spiritual part and the physical part of a person. (See: [[rc://en/ta/man/translate/figs-merism]])
This compares either the forests and farmlands of Assyria or the army of Assyria to a sick man as he lies in bed dying. This emphasizes how something so great can become weak and dying. AT: "they will be like a sick man who grows weak and dies" (See: [[rc://en/ta/man/translate/figs-simile]])