Following are a number of back-translations as well as a sample translation for translators of Jeremiah 49:31:

• Kupsabiny: “Go (plur.) and fight a nation that lives in peace,
  a community that believes that they have sufficient peace.
  A community that has not built a wall or doors of iron.
  People who stay minding their own business.” (Source: Kupsabiny Back Translation)
• Hiligaynon: “I, the LORD, commanded them, ‘Attack the people who are at ease and have no trouble. Their city has no gates or bars and they live just all-by-themselves.” (Source: Hiligaynon Back Translation)
• English: “But I say to Nebuchadnezzar,
  ‘Go up and attack that nation whose people feel secure;
  they do not have allies who will help them and do not have walls with gates that have bars in them.” (Source: Translation for Translators)