When the Supreme Personality of Godhead was speaking as an innocent boy in very sweet words, Vasudeva and Devakī became captivated by parental affection and embraced Him with great pleasure. They were amazed and could not speak or answer the words of Kṛṣṇa but simply embraced Him and Balarāma in great affection and remained silent, shedding incessant tears.
Thus having consoled His father and mother, the Supreme Personality of Godhead, appearing as the beloved son of Devakī, approached His grandfather Ugrasena and announced that Ugrasena would now be the King of the Yadu kingdom. Kaṁsa had been forcibly ruling the kingdom of Yadu, in spite of the presence of his father, whom he had arrested. But after the death of Kaṁsa, his father was released and announced to be the monarch of the Yadu kingdom. It appears that in those days in the western part of India there were many small kingdoms, ruled by the Yadu dynasty, Andhaka dynasty, Vṛṣṇi dynasty and Bhoja dynasty. Mahārāja Ugrasena belonged to the Bhoja dynasty; therefore Kṛṣṇa indirectly declared that the King of the Bhoja dynasty would be the emperor of the other small kingdoms. Kṛṣṇa willingly asked Mahārāja Ugrasena to rule over Himself and Balarāma because They were his subjects. The word prajā is used both for progeny and for citizens, so Kṛṣṇa belonged to the prajā, both as a grandson of Mahārāja Ugrasena's and as a member of the Yadu dynasty. Thus He voluntarily accepted the rule of Mahārāja Ugrasena. He informed Ugrasena, "Being cursed by Yayāti, the kings of the Yadu dynasty may not occupy the throne. It will be Our pleasure to act as your servants. My full cooperation with you will make your position more exalted and secure so that the kings of other dynasties will not hesitate to pay their respective revenues. Protected by Me, you will be honored even by the demigods from the heavenly planets. My dear grandfather, out of fear of My late uncle Kaṁsa, all the kings belonging to the Yadu, Vṛṣṇi, Andhaka, Madhu, Daśārha and Kukura dynasties were very anxious and disturbed. Now you can pacify them all and give them assurance of security. The whole kingdom will be peaceful."
All the kings in the neighboring area had left their homes in fear of Kaṁsa and were living in distant parts of the country. Now, after the death of Kaṁsa and the reinstallment of Ugrasena as king, the neighboring kings were given all kinds of presentations and comforts. Then they returned to their respective homes. After this nice political arrangement, the citizens of Mathurā were pleased to live in Mathurā, being protected by the strong arms of Kṛṣṇa and Balarāma. On account of good government in the presence of Kṛṣṇa and Balarāma, the inhabitants of Mathurā felt complete satisfaction in the fulfillment of all their material desires and necessities, and because they saw Kṛṣṇa and Balarāma daily, face to face, they soon forgot all material miseries completely. As soon as they saw Kṛṣṇa and Balarāma coming out on the street, very nicely dressed and smiling and looking at the citizens with grace, the citizens were immediately filled with loving ecstasies simply by seeing the personal presence of Mukunda. The name Mukunda refers to one who can award liberation and transcendental bliss. Kṛṣṇa's presence acted as such a vitalizing tonic that not only the younger generation but even the old men of Mathurā became fully invigorated with youthful energy and strength by regularly seeing Him.
Nanda Mahārāja and Yaśodā were also living in Mathurā because Kṛṣṇa and Balarāma were there, but after some time they wanted to go back to Vṛndāvana. Kṛṣṇa and Balarāma went before Nanda and Yaśodā and very affectionately embraced them, and then the two Lords spoke as follows: “Dear father and mother, although We were born of Vasudeva and Devakī, you have been Our real father and mother, because from Our very birth and childhood you raised Us with great affection and love. Your affectionate love for Us was more than anyone can offer one's own children. You are actually Our father and mother, because you raised Us as your own children when We were just like orphans. For certain reasons We were rejected by Our father and mother, and you protected Us. Dear father and mother, We know that you will feel separation upon returning to Vṛndāvana and leaving Us here, but please rest assured that We shall come back to Vṛndāvana just after giving some satisfaction to Our real father and mother, Vasudeva and Devakī, and Our grandfather and other family members.” Kṛṣṇa and Balarāma thus satisfied Nanda and Yaśodā by sweet words and by presentations of various kinds of clothing, ornaments and copper utensils. They satisfied them, along with their friends and neighbors who had come with them from Vṛndāvana to Mathurā, as fully as possible. On account of excessive parental affection for Balarāma and Kṛṣṇa, Nanda Mahārāja felt tears in his eyes, and he embraced Them and started with the cowherd men for Vṛndāvana.
After this, Vasudeva had his sons initiated by sacred thread as the token of second birth, which is essential for the higher castes of human society. Vasudeva called for his family priest and learned brāhmaṇas, and the sacred thread ceremony of Kṛṣṇa and Balarāma was duly performed. During this ceremony, Vasudeva gave various ornaments in charity to the brāhmaṇas and endowed them with cows decorated with silken cloths and golden ornaments. Then Vasudeva remembered the cows he had wanted to give in charity to the brāhmaṇas after the birth of Kṛṣṇa and Balarāma. But being imprisoned by Kaṁsa at that time, Vasudeva had been able to do so only within his mind, for Kaṁsa had stolen all his cows. With the death of Kaṁsa his cows were released, and now Vasudeva gave the actual cows to the brāhmaṇas. Then Balarāma and Kṛṣṇa were duly initiated with the sacred thread ceremony, and They repeated the chanting of the Gāyatrī mantra. The Gāyatrī mantra is offered to disciples after the sacred thread ceremony, and Balarāma and Kṛṣṇa properly discharged the duties of chanting this mantra. Anyone who executes the chanting of this mantra has to abide by certain principles and vows. Although Balarāma and Kṛṣṇa are transcendental personalities, They strictly followed the regulative principles. They were initiated by Their family priest, Gargācārya, usually known as Garga Muni, the ācārya of the Yadu dynasty. According to Vedic culture, every respectable family has an ācārya, or spiritual master. One is not considered a perfectly cultured man without being initiated and trained by an ācārya. It is said, therefore, that one who has approached an ācārya is actually in perfect knowledge. Lord Kṛṣṇa and Lord Balarāma are the Supreme Personality of Godhead, the master of all education and knowledge. There was no need for Them to accept a spiritual master, or ācārya, yet for the instruction of ordinary men They also accepted a spiritual master for advancement in spiritual knowledge.
It is customary, after being initiated in the Gāyatrī mantra, for one to live away from home for some time under the care of the ācārya, to be trained in spiritual life. During this period, one has to work under the spiritual master as an ordinary menial servant. There are many rules and regulations for a brahmacārī living under the care of an ācārya, and Kṛṣṇa and Balarāma strictly followed those regulative principles while living under the instruction of their spiritual master, Sāndīpani Muni, who was a resident of Avantīpura, in the northern Indian district of Ujjain. According to scriptural injunctions, a spiritual master should be respected and regarded on an equal level with the Supreme Personality of Godhead. Kṛṣṇa and Balarāma exactly followed those principles with great devotion and underwent the regulations of brahmacarya. Thus They satisfied Their spiritual master, who instructed Them in Vedic knowledge. Being very satisfied, Sāndīpani Muni instructed Them in all the intricacies of Vedic wisdom and in supplementary literature such as the Upaniṣads. Because Kṛṣṇa and Balarāma happened to be kṣatriyas, They were specifically trained in military science, politics and ethics. Politics includes such departments of knowledge as how to make peace, how to fight, how to pacify, how to divide and rule and how to give shelter. All these items were fully explained and instructed to Kṛṣṇa and Balarāma.