I have seen folly— Jeremiah draws a contrast between the sins of the prophets of Samaria, and of Jerusalem, and pronounces those of the latter to be more enormous, because the former seduced the people by prophesying in the name of Baal; whereas the prophets of Israel pronounced their false prophesies in the name of the true God, and pretended that he was the author of all their impostures. The wickedness of their lives also reflected a dishonour upon God and his religion. See Calmet and Lowth.
Related Commentaries of Jeremiah 23:13
Jeremiah 23:13-14
13 And I have seen follyb in the prophets of Samaria; they prophesied in Baal, and caused my people Israel to err.
14 I have seen also in the prophets of Jerusalem an horrible thing: they commit adultery, and walk in lies: they strengthen also the hands of evildoers, that none doth return from his wickedness: they are all of them unto me as Sodom, and the inhabitants thereof as Gomorrah.