Charles Ellicott Commentary Jeremiah 6:18

"Therefore hear, ye nations, and know, O congregation, what is among them." — Jeremiah 6:18 (ASV)

Therefore hear, ye nations ... — The obstinate refusal with which the people met the summons of the prophet leads him once more to a solemn appeal. He appeals:

1. To the heathen nations.
2. Then to the “congregation” of Israel (as in Exodus and Numbers, throughout), or possibly to mankind collectively.
3. To earth as the witness of the judgments of Jehovah.

What is among them. — Better, what comes to pass for them, i.e., for the sinful people.