Vishnupurana 3.8.28

3.8.28

dharitrīpālanenaiva kṛtakṛtyo narādhipaḥ
bhavanti nṛpater aṃśā yato yajñādikarmaṇām //

"The man of the warrior tribe should cheerfully give presents to Brahmans, perform various sacrifices, and study the scriptures. His especial sources of maintenance are arms and the protection of the earth. The guardianship of the earth is indeed his especial province: by the discharge of this duty a king attains his objects, and realizes a share of the merit of all sacrificial rites. By intimidating the bad, and cherishing the good, the monarch who maintains the discipline of the different castes secures whatever region he desires.