Ramayana
वक्तव्यश्चेति नृपतिर्धमेण सुसमाहितः । यथा भ्रातृषु वर्तेथास्तथा पौरेषु नित्यदा ॥ 7-48-14 ॥
And the king, steadfast in righteousness, must be told this: that you should always conduct yourself toward the citizens as you do toward your brothers.
english translation