400
Śrīmad-Bhāgavatam
[Canto 4, Ch. 9]
to be  mukta  or  brahma-bhūta . It is said in  Bhagavad-gītā  that a devotee is considered to be on the  brahma-bhūta  platform when he has no material contamination. In the  Padma Purāṇa  this is also confirmed:  mukti  means engagement in the service of the Lord.
The great sage Maitreya explained that Dhruva Mahārāja did not desire in the beginning to engage in the service of the Lord, but he wanted an exalted position better than his great-grandfather's. This is more or less not service to the Lord but service to the senses. Even if one gets the position of Brahmā, the most exalted position in this material world, he is a conditioned soul. Śrīla Prabodhānanda Sarasvatī says that if one is elevated to real, pure devotional service, he considers even great demigods like Brahmā and Indra to be on an equal level with an insignificant insect. The reason is that an insignificant insect has a desire for sense gratification, and even a great personality like Lord Brahmā also wants to dominate this material nature.
Sense gratification means domination over material nature. The whole competition between conditioned souls is based upon domination of this material nature. Modern scientists are proud of their knowledge because they are discovering new methods to dominate the laws of material nature. They think that this is the advancement of human civilization—the more they can dominate the material laws, the more advanced they think they are. Dhruva Mahārāja's propensity in the beginning was like that. He wanted to dominate this material world in a greater position than Lord Brahmā. Therefore elsewhere it is described that after the appearance of the Lord, when Dhruva Mahārāja thought and compared his determination to his final reward, he realized that he had wanted a few particles of broken glass but instead had received many diamonds. As soon as he saw the Supreme Personality of Godhead face to face, he immediately became conscious of the unimportance of his demand from the Lord to have an exalted position better than Lord Brahmā's.
When Dhruva Mahārāja became situated on the  vāsudeva  platform due to seeing the Lord face to face, all his material contamination was cleared. Thus he became ashamed of what his demands were and what he had achieved. He was very much ashamed to think that although he had gone to Madhuvana, giving up the kingdom of his father, and he had gotten a spiritual master like Nārada Muni, still he was thinking of revenge against his stepmother and wanted to occupy an exalted post within this material world. These were the causes for his moroseness even after he received all the desired benedictions from the Lord.