SB 4.9.30

dhruva uvāca
samādhinā naika-bhavena yat padaṁ
 viduḥ sanandādaya ūrdhva-retasaḥ
māsair ahaṁ ṣaḍbhir amuṣya pādayoś
 chāyām upetyāpagataḥ pṛthaṅ-matiḥ
Synonyms: 
dhruvaḥ uvāca — Dhruva Mahārāja said; samādhinā — by practicing yoga in trance; na — never; eka-bhavena — by one birth; yat — which; padam — position; viduḥ — understood; sananda-ādayaḥ — the four brahmacārīs headed by Sanandana; ūrdhva-retasaḥ — infallible celibates; māsaiḥ — within months; aham — I; ṣaḍbhiḥ — six; amuṣya — of Him; pādayoḥ — of the lotus feet; chāyām — shelter; upetya — achieving; apagataḥ — fell down; pṛthak-matiḥ — my mind fixed on things other than the Lord.
Translation: 
Dhruva Mahārāja thought to himself: To endeavor to be situated in the shade of the lotus feet of the Lord is not an ordinary task, because even the great brahmacārīs headed by Sanandana, who practiced aṣṭāṅga-yoga in trance, attained the shelter of the Lord’s lotus feet only after many, many births. Within six months I achieved the same result, yet due to my thinking differently from the Lord, I fell down from my position.
Purport: 

In this verse Dhruva Mahārāja himself explains the cause of his moroseness. First he laments that to see the Supreme Personality of Godhead directly is not easy. Even great saintly persons like the four celebrated brahmacārīs headed by Sanandana — Sanandana, Sanaka, Sanātana and Sanat-kumāra — practiced the yoga system for many, many births and remained in trance before getting the opportunity to see the Supreme Lord face to face. As far as Dhruva Mahārāja was concerned, he saw the Supreme Lord personally after only six months of practice in devotional service. He expected, therefore, that as soon as he met the Supreme Lord, the Lord would take him to His abode immediately, without waiting. Dhruva Mahārāja could understand very clearly that the Lord had offered him the rule of the world for thirty-six thousand years because in the beginning he was under the spell of the material energy and wanted to take revenge against his stepmother and rule over his father’s kingdom. Dhruva Mahārāja greatly lamented his propensity for ruling the material world and his revengeful attitude towards other living entities.