Jeremiah 38:6-7

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. But Ebed-melech the Ethiopian, an important court official, heard that Jeremiah was in the cistern. At that time the king was holding court at the Benjamin Gate