"Pariksit Maharaja was an ideal king and householder because he was a devotee of the Personality of Godhead. A devotee of the Lord automatically has all good qualifications. And the Emperor was a typical example of this. Personally he had no attachment for all the worldly opulences in his possession. But since he was king for the all-around welfare of his citizens, he was always busy in the welfare work of the public, not only for this life, but also for the next. He would not allow slaughterhouses or killing of cows. He was not a foolish and partial administrator who would arrange for the protection of one living being and allow another to be killed. Because he was a devotee of the Lord, he knew perfectly well how to conduct his administration for everyone's happiness--men, animals, plants and all living creatures. He was not selfishly interested. Selfishness is either self-centered or self-extended. He was neither. His interest was to please the Supreme Truth, Personality of Godhead. The king is the representative of the Supreme Lord, and therefore the king's interest must be identical with that of the Supreme Lord. The Supreme Lord wants all living beings to be obedient to Him and thereby become happy. Therefore the king's interest is to guide all subjects back to the kingdom of God. Hence the activities of the citizens should be so coordinated that they can at the end go back home, back to Godhead. Under the administration of a representative king, the kingdom is full of opulence. At that time, human beings need not eat animals. There are ample food grains, milk, fruit and vegetables so that the human beings as well as the animals can eat sumptuously and to their heart's content. If all living beings are satisfied with food and shelter and obey the prescribed rules, there cannot be any disturbance between one living being and another. Emperor Pariksit was a worthy king, and therefore all were happy during his reign."

Srimad-bhagavatam 1-4-12 Purport

"Once, when Maharaja Pariksit was on his way to conquer the world, he saw the master of Kali-yuga, who was lower than a sudra, disguised as a king and hurting the legs of a cow and bull. The King at once caught hold of him to deal sufficient punishment."

"The purpose of a king's going out to conquer the world is not for self-aggrandizement. Maharaja Pariksit went out to conquer the world after his ascendance to the throne, but this was not for the purpose of aggression on other states. He was the Emperor of the world, and all small states were already under his regime. His purpose in going out was to see how things were going on in terms of the godly state. The king, being the representative of the Lord, has to execute the will of the Lord duly. There is no question of self-aggrandizement. Thus as soon as Maharaja Pariksit saw that a lower-class man in the dress of a king was hurting the legs of a cow and a bull, at once he arrested and punished him. The king cannot tolerate insults to the most important animal, the cow, nor can he tolerate disrespect for the most important man, the brahmana. Human civilization means to advance the cause of brahminical culture, and to maintain it, cow protection is essential. There is a miracle in milk, for it contains all the necessary vitamins to sustain human physiological conditions for higher achievements. Brahminical culture can advance only when man is educated to develop the quality of goodness, and for this there is a prime necessity of food prepared with milk, fruits and grains. Maharaja Pariksit was astonished to see that a black sudra, dressed like a ruler, was mistreating a cow, the most important animal in human society.

The age of Kali means mismanagement and quarrel. And the root cause of all mismanagement and quarrel is that worthless men with the modes of lower-class men, who have no higher ambition in life, come to the helm of the state management. Such men at the post of a king are sure to first hurt the cow and the brahminical culture, thereby pushing all society towards hell. Maharaja Pariksit, trained as he was, got the scent of this root cause of all quarrel in the world. Thus he wanted to stop it in the very beginning."

Srimad-bhagavatam 1-16-4 Text and Purport
Bhaktivedanta Book Trust. HDG A.C. Bhaktivedanta Swami Srila Prabhupada.