Mahabharata Santi Parva Chapter 64:2

Mahabharata Santi Parva (Rajadharmanusasana Parva) Chapter 64:2 Mandhatri said, 'I bend my head for gratifying thee. Without doubt, however, I desire to see the first of gods, O divine Lord! Casting off all (earthly) desires, I wish to earn religious merit, and to lead the foremost mode of life, that path of the good, highly regarded by all. By exercising the high duties of a Kshatriya, I have earned many regions of inexhaustible merit in the other world, and I have also, through those duties, spread my fame. I do not, however, know how to discharge those duties, the foremost in the world, that have flowed from the first of gods.' Indra said, 'They that are not kings, however observant they may be of their duties, cannot easily attain the highest rewards of duty. Kingly duties first flowed from the original god. Other duties flowed afterwards from his body. Infinite were the other duties, with those of the Vanaprastha mode of life, that were created afterwards. The fruits of all those are exhaustible. Kingly duties, however, are distinguished above them. In them are included all other duties. For this reason Kshatriya duties are said to be the foremost of all. In days of old, Vishnu, by acting according to Kshatriya duties, forcibly suppressed and destroyed his foes and thereby afforded relief to the gods and the Rishis of immeasurable energy. If the divine Vishnu of inconceivable energy had not slain all his foes among the Asuras, then the Brahmanas, and (Brahman) the Creator of the worlds and Kshatriya duties, and the duties that first flowed from the Supreme deity, would all have been destroyed. If that first and foremost of gods had not, by putting forth his prowess, subjugated the earth with all her Asuras, then all the duties, of the four orders and all the duties in respect of the four modes of life would all have been destroyed in consequence of the destruction of Brahmanas. The eternal duties (of men) had all suffered destruction. It was by the exercise of Kshatriya duties that they were revived.In every Yuga, the duties of Brahmanas in respect of attaining to Brahma first set in. These, however, are all protected by kingly duties. The latter, on this account, are regarded as the foremost. Casting away life in battle, compassion for all creatures, knowledge of the affairs of the world, protection of men, rescuing them from danger, relieving the distressed and the oppressed, all these occur among Kshatriya duties practised by Kings. Persons that do not regard wholesome restraints and that are governed by lust and wrath, do not commit overt acts of sin from fear of kings. Others that are docile and of righteous behaviour succeed, in consequence of the same influence, in performing all their duties. For this reason Kshatriya duties are regarded to be righteous. Without doubt, all creatures live happily in the world, protected by kings exercising Kshatriya duties like children protected by their parents. Kshatriya duties are the foremost of all duties. Those eternal duties, regarded as the first in the world, embrace the protection of every creature. Themselves eternal, they lead to eternal emancipation.'