Jeremiah 38:10

Then the king commanded Ebed-melech, the Ethiopian, saying, Take from hence thirty men with thee, a sufficiently large squad under his command to protect Jeremiah in case some of the princes or their retainers should attempt to interfere with the work of rescuing the prophet, and take up Jeremiah, the prophet, out of the dungeon before he die. The remonstrance of Ebed-melech had had at least this much effect upon Zedekiah, that he determined to prevent outright murder.