10 Then the king commanded Ebedmelech the Ethiopian, saying, Take from hence 30 men with thee, and take up Jeremiah the prophet out of the dungeon, before he die.

The dungeon must have been open to the rain, causing the bottom to be miry (see Psa. 69:2, 4, where such experiences foreshadow those of Christ). The pit is a symbol of the grave, and thus there is in type the accusations against The Lord Yahshua, his trial, and crucifixion.

Though the prophet sank into the grave, he was raised again therefrom, as later did the The Lord Yahshua. Jeremiah is rescued from the pit by a friend, Ebedmelech, a despised Ethiopian, who demonstrates a more spiritual attitude than revealed by the Jews at that time.

He must have been a humane and noble character, to have thus raised his voice against the powerful faction. But if Jeremiah sank into the pit literally, Zedekiah the king sank into the pit figuratively. ...*

20 But Jeremiah said, They shall not deliver thee. Obey, I beseech thee, the voice of Yahweh, which I speak unto thee: so it shall be well unto thee, and thy soul shall live.

The final address of the faithful Jeremiah urges the people to obedience.

But his voice is to no avail, as he remained in the court of the prison until the day that Jerusalem was taken. In this the iniquity of his people was laid upon him, and he bore the sins of many.