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,
If one wants to capture Him, one must undertake devotional service.
Srimad Bhagavatam 10.9.10,
One should not be impatient in discharging devotional service, but should take instruction from the spiritual master and execute them with patience depending on the mercy of Guru and Krishna. The successful execution of Krishna conscious activities requires both patience and confidence? The devotee thinks "Krishna will surely protect me and give me help for the successful execution of devotional service." This is called confidence. — The Nectar of instruction, Text 03.
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,
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.
Teach them Krishna Conscious Art at early age, so they may advance in devotional Service.