Albert Barnes Commentary Jeremiah 11:9

"And Jehovah said unto me, A conspiracy is found among the men of Judah, and among the inhabitants of Jerusalem." — Jeremiah 11:9 (ASV)

A conspiracy - The defection from the covenant was as general as if it had been the result of preconcerted arrangement. The decided course taken by Josiah may, however, have led the opposite party to secret combinations against him.