SB 4.21.22

ahaṁ daṇḍa-dharo rājā
 prajānām iha yojitaḥ
rakṣitā vṛttidaḥ sveṣu
 setuṣu sthāpitā pṛthak
Synonyms: 
aham — I; daṇḍa-dharaḥ — carrier of the scepter; rājā — king; prajānām — of the citizens; iha — in this world; yojitaḥ — engaged; rakṣitā — protector; vṛtti-daḥ — employer; sveṣu — in their own; setuṣu — respective social orders; sthāpitā — established; pṛthak — differently.
Translation: 
King Pṛthu continued: By the grace of the Supreme Lord I have been appointed the king of this planet, and I carry the scepter to rule the citizens, protect them from all danger, and give them employment according to their respective positions in the social order established by Vedic injunction.
Purport: 

A king is supposed to be appointed by the Supreme Personality of Godhead to look after the interests of his particular planet. On every planet there is a predominating person, just as we now see that in every country there is a president. If one is president or king, it should be understood that this opportunity has been given to him by the Supreme Lord. According to the Vedic system, the king is considered a representative of Godhead and is offered respects by the citizens as God in the human form of life. Actually, according to Vedic information, the Supreme Lord maintains all living entities, and especially human beings, to elevate them to the highest perfection. After many, many births in lower species, when a living entity evolves to the human form of life and in particular to the civilized human form of life, his society must be divided into four gradations, as ordered by the Supreme Personality of Godhead in Bhagavad-gītā (cātur-varṇyaṁ mayā sṛṣṭam, etc.). The four social orders — the brāhmaṇas, kṣatriyas, vaiśyas and śūdras — are natural divisions of human society, and as declared by Pṛthu Mahārāja, every man in his respective social order must have proper employment for his livelihood. It is the duty of the king or the government to insure that the people observe the social order and that they are also employed in their respective occupational duties. In modern times, since the protection of the government or the king has been withdrawn, social order has practically collapsed. No one knows who is a brāhmaṇa, who is a kṣatriya, who is a vaiśya or who is a śūdra, and people claim to belong to a particular social order by birthright only. It is the duty of the government to reestablish social order in terms of occupational duties and the modes of material nature, for that will make the entire world population actually civilized. If it does not observe the institutional functions of the four social orders, human society is no better than animal society, in which there is never tranquillity, peace and prosperity but only chaos and confusion. Mahārāja Pṛthu, as an ideal king, strictly observed the maintenance of the Vedic social order.

Prajāyate iti prajā. The word prajā refers to one who takes birth. Therefore Pṛthu Mahārāja guaranteed protection for prajānām — all living entities who took birth in his kingdom. Prajā refers not only to human beings but also to animals, trees and every other living entity. It is the duty of the king to give all living entities protection and food. The fools and rascals of modern society have no knowledge of the extent of the responsibility of the government. Animals are also citizens of the land in which they happen to be born, and they also have the right to continue their existence at the cost of the Supreme Lord. The disturbance of the animal population by wholesale slaughter produces a catastrophic future reaction for the butcher, his land and his government.