The manifestation of unadulterated devotional service is exhibited when one’s mind is at once attracted to hearing the transcendental name and qualities of the Supreme Personality of Godhead, who is residing in everyone’s heart.
Srimad Bhagavatam 3.29.11-12,
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.
By rendering devotional service unto the Personality of Godhead, Sri Krishna, one immediately acquires causeless knowledge and detachment from the world.
The child cries to have toys, but one who can cry for the Lord in love is certainly successful in the line of devotional service.
Devotional service to Krishna is the chief function of the living entity. There are different methods for the liberation of the conditioned soul Karma, jnana, yoga and Bhakti but all are dependent on bhakti. — Sri Caitanya Caritamrita, Madhya lila, 22.17.
Meditation means stopping all nonsensical activities, at least for the time being. Devotional service, however, not only puts an end to all nonsensical mundane activities, but also engages one in meaningful devotional activities. — The Nectar of instruction, Text 02