Ramayana
अधीतस्य च तप्तस्य कर्मणः सुकृतस्य च । षष्ठं भजति भागं तु प्रजा धर्मेण पालयन् ॥ 7-74-30 ॥
A king who protects his subjects with righteousness obtains a sixth part of their study, their austerity, their ritual acts, and their good deeds.
english translation