Charles Ellicott Commentary Jeremiah 23:13

"And I have seen folly in the prophets of Samaria; they prophesied by Baal, and caused my people Israel to err." — Jeremiah 23:13 (ASV)

I have seen folly ... —Literally, as in Job 6:6, that which is unsavoury — i.e., insipid, and so, ethically, foolish. The guilt of the prophets of Samaria cannot be passed over, but it is noticed, as in Jeremiah 3:6-10, only in order to compare it with the darker evils of those of Judah and Jerusalem.

They prophesied in Baal. —i.e., in the name and as if by the power of Baal. Compare to 1 Kings 18:19; 1 Kings 22:6–7.