Jeremiah 38:6, 10-13

So the officials took Jeremiah from his cell and lowered him by ropes into an empty cistern in the prison yard. It belonged to Malkijah, a member of the royal family. There was no water in the cistern, but there was a thick layer of mud at the bottom, and Jeremiah sank down into it.

So the king told Ebed-melech, “Take thirty of my men with you, and pull Jeremiah out of the cistern before he dies.” So Ebed-melech took the men with him and went to a room in the palace beneath the treasury, where he found some old rags and discarded clothing. He carried these to the cistern and lowered them to Jeremiah on a rope. Ebed-melech called down to Jeremiah, “Put these rags under your armpits to protect you from the ropes.” Then when Jeremiah was ready, they pulled him out. So Jeremiah was returned to the courtyard of the guard—the palace prison—where he remained.