According to Jeremiah, God told Jeremiah to tell Seraiah, a calm and important helper of the king, some special words when he traveled with King Zedekiah to Babylon. Seraiah had a quiet and peaceful job, helping the king during a tricky time.
Jeremiah 51:59: The word which Jeremiah the prophet commanded Seraiah the son of Neriah, the son of Maaseiah, when he went with Zedekiah the king of Judah into Babylon in the fourth year of his reign. And [this] Seraiah [was] a quiet prince. [with: or, on the behalf of] [quiet...: or, prince of Menucha, or, chief chamberlain]
Amos 3:7 states that the LORD does nothing without revealing His plan to His servants, the prophets. This seems to contrast with Jeremiah 51:59 where a command is given to Seraiah, a non-prophet, without the typical prophetic revelation context.
Amos 3:7: Surely the Lord GOD will do nothing, but he revealeth his secret unto his servants the prophets.