Srila Prabhupada explains the importance of pure bhakti where there is no expectation of return.
It is said that without the blessings of Hari, the Supreme Personality of Godhead, no one can stop the continuous chain of birth and death within this material world. Therefore the Supreme Lord is also called bhava-cchit. The Vaisnava philosophy in the process of Krsna consciousness prohibits the devotee from all kinds of material aspirations. A Vaisnava devotee should always be anyabhilasita-sunya, free from all material aspirations for the results of fruitive activities or empiric philosophical speculation. Dhruva Maharaja was actually initiated by Narada Muni, the greatest Vaisnava, in the chanting of om namo bhagavate vasudevaya. This mantra is a visnu-mantra, for by practicing the chanting of this mantra one is elevated to the Visnuloka. Dhruva Maharaja regrets that although he was initiated in the visnu-mantra by a Vaisnava, he still aspired for material benefits. That was another cause for lamentation. Although he got the result of the visnu-mantra by the causeless mercy of the Lord, he lamented how foolish he was to have strived for material benefits while practicing devotional service. In other words, every one of us who is engaged in devotional service in Krsna consciousness should be completely free from all material aspirations. Otherwise we will have to lament like Dhruva Maharaja.