According to the prophet Jeremiah, God promised to bring back all the special items taken from His house by the king of Babylon in two years. This means God would make sure everything would come home safely.
Jeremiah 28:3: Within two full years will I bring again into this place all the vessels of the LORD'S house, that Nebuchadnezzar king of Babylon took away from this place, and carried them to Babylon: [two...: Heb. two years of days]
Jeremiah 29:10 says that the captivity would last seventy years, contradicting Jeremiah 28:3's prophecy of two years.
Jeremiah 29:10: For thus saith the LORD, That after seventy years be accomplished at Babylon I will visit you, and perform my good word toward you, in causing you to return to this place.