Srimad Bhagavatam 4.12.42: The great sage Nārada continued: Just see how Dhruva Mahārāja, aggrieved at the harsh words of his stepmother, went to the forest at the age of only five years and under my direction underwent austerity. Although the Supreme Personality of Godhead is unconquerable, Dhruva Mahārāja defeated Him with the specific qualifications possessed by the Lord's devotees.
The Supreme Godhead is unconquerable; no one can conquer the Lord. But He voluntarily accepts subordination to the devotional qualities of His devotees. For example, Lord Kṛṣṇa accepted subordination to the control of mother Yaśodā because she was a great devotee. The Lord likes to be under the control of His devotees. In the Caitanya-caritāmṛta it is said that everyone comes before the Lord and offers Him exalted prayers, but the Lord does not feel as pleased when offered such prayers as He does when a devotee, out of pure love, chastises Him as a subordinate. The Lord forgets His exalted position and willingly submits to His pure devotee. Dhruva Mahārāja conquered the Supreme Lord because at a very tender age, only five years old, he underwent all the austerities of devotional service. This devotional service was of course executed under the direction of a great sage, Nārada. This is the first principle of devotional service — ādau gurv-āśrayam. In the beginning one must accept a bona fide spiritual master, and if a devotee follows strictly the direction of the spiritual master, as Dhruva Mahārāja followed the instruction of Nārada Muni, then it is not difficult for him to achieve the favor of the Lord.
The sum total of devotional qualities is development of unalloyed love for Kṛṣṇa. This unalloyed love for Kṛṣṇa can be achieved simply by hearing about Kṛṣṇa. Lord Caitanya accepted this principle — that if one in any position submissively hears the transcendental message spoken by Kṛṣṇa or about Kṛṣṇa, then gradually he develops the quality of unalloyed love, and by that love only he can conquer the unconquerable. The Māyāvādī philosophers aspire to become one with the Supreme Lord, but a devotee surpasses that position. Not only does a devotee become one in quality with the Supreme Lord, but he sometimes becomes the father, mother or master of the Lord. Arjuna also, by his devotional service, made Lord Kṛṣṇa his chariot driver; he ordered the Lord, "Put my chariot here," and the Lord executed his order. These are some examples of how a devotee can acquire the exalted position of conquering the unconquerable.