It appears that King Zedekiah wants to redeem himself and sends word to Jeremiah to pray. But, of course, Jeremiah sent back some words that the king didn't want to hear.  The results?  Jeremiah is thrown into a cell in a dungeon.  The Hebrew word for vaulted cell gives the impression that this place was something like a bank vault, with no windows.

Jeremiah certainly is given reason to be called “the weeping prophet” considering all the things that happened to him. One man (Ebed-Melech, a Cushite, an official in the royal palace) was filled with compassion for Jeremiah and was brave enough to go to the king on Jeremiah’s behalf.

Jer 38:9-10
"My lord the king, these men have acted wickedly in all they have done to Jeremiah the prophet. They have thrown him into a cistern, where he will starve to death when there is no longer any bread in the city." Then the king commanded Ebed-Melech the Cushite, "Take thirty men from here with you and lift Jeremiah the prophet out of the cistern before he dies."

Ebed-Melech was later rewarded for his trust in the Lord.

Jer 39:16-18
"Go and tell Ebed-Melech the Cushite, 'This is what the LORD Almighty, the God of Israel, says: I am about to fulfill my words against this city through disaster, not prosperity. At that time they will be fulfilled before your eyes. But I will rescue you on that day, declares the LORD; you will not be handed over to those you fear. I will save you; you will not fall by the sword but will escape with your life, because you trust in me, declares the LORD.'"

When we trust in the Lord, He rewards us too! How awesome is that!