Significance of Devotional Service
Without devotional service, all other methods for spiritual self-realization are weak and insignificant. Unless one comes to the devotional service of Lord Krishna, jnana yoga cannot give the desired results.
Satisfaction Derived From Devotional Service
It is true that by practicing restraint of the senses by the yoga system one can get relief from the disturbances of desire and lust, but this is not sufficient to give satisfaction to the soul, for this satisfaction is derived from devotional service to the Supreme Personality of Godhead. — Srimad Bhagavatam, 01.16.35.
Understanding The Supreme Lord
One can understand the Supreme Personality as He is only by devotional service and when he is in full consciousness of the Supreme Lord by such devotion, he can enter into the kingdom of God. — Bhagavad Gita, 18.55.
Kingdom of Godhead
The Kingdom of Godhead is not a myth but it is situated far beyond the boundary of the material cosmos and one can know it by the process of devotional service only.
Sincere Devotional Service
If one renders even a small amount of sincere devotional Service, Krishna becomes obliged to elevate such person and what to speak of one whose entire life and soul has been dedicated to Krishna’s service. — Letter to Harer Nama, 06th Nov, 1969.
Real Result of Devotional Service
The real result of devotional service is the awakening of pure love for the Supreme Personality of Godhead, which continues under all circumstances.
Srimad Bhagavatam 5.24.19,
Srila Prabhupada