yì​zhī​suǒ​zài

where duty lies

  1. justice
    (bound form) justice; righteousness; upright behavior
  2. zhī particle
    [possessive]
    Connects a describing word or phrase to the noun it describes, similar to de but used in formal or literary writing.
  3. where something lies
    the place where something exists or resides, often used after a noun to indicate the heart or essence of a matter