Following are a number of back-translations as well as a sample translation for translators of Isaiah 26:4:

• Kupsabiny: “Always trust (plur.) in God,
  because he is your shield forever.” (Source: Kupsabiny Back Translation)
• Newari: “Always keep putting your trust in the LORD,
  for he is the always-existing rock.” (Source: Newari Back Translation)
• Hiligaynon: “‘You (plur.) trust in the LORD always for the LORD is our (incl.) rock of refuge/protecting until whenever/(everlasting).” (Source: Hiligaynon Back Translation)
• English: “So always trust in Yahweh,
  because Yahweh, our God, is forever like a huge rock under which we are sheltered/protected/safe.” (Source: Translation for Translators)