Charles Ellicott Commentary Jeremiah 3:21

"A voice is heard upon the bare heights, the weeping [and] the supplications of the children of Israel; because they have perverted their way, they have forgotten Jehovah their God." — Jeremiah 3:21 (ASV)

A voice was heard. —Yes, the guilty wife was there, but she was also penitent. The “high places” which had been the scene of the guilt of the sons of Israel, where the cries of their orgiastic worship had been heard, now echoed with their weeping and supplication (or, more literally, the weeping of suppliant prayers), as they called to mind the hateful sins of the past.