RobH_en_tn/2ki/19/07.md

I will put a spirit in him, and he will hear a certain report and go back to his own land

"I will control the attitude of the king of Assyria, so when he hears a report, he will want to return to his own country"

I will put a spirit in him

"I will influence his thinking" or "I will cause him to think differently." Here "spirit" probably refers to his attitude and thoughts, rather than to a spirit being.

I will cause him to fall by the sword

"Fall by the sword" is metonymy for being killed. AT: "I will cause him to die by the sword" or "I will cause some men to kill him with a sword" (See: rc://en/ta/man/translate/figs-metonymy)