SB 4.8.38
nunam bhavan bhagavato
yo ’ngajah paramesthinah
vitudann atate vinam
hitaya jagato ’rkavat
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
My dear lord, you are a worthy son of Lord Brahma, and you travel, playing on your musical instrument, the vina, for the welfare of the entire universe. You are like the sun, which rotates in the universe for the benefit of all living beings.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
Dhruva Maharaja, although a young child, expressed his hope that he might be offered the benediction of a kingdom which would exceed in opulence those of his father and grandfather. He also expressed his gladness that he had met such an exalted person as Narada, whose only concern was to illuminate the world, like the sun, which rotates all over the universe only for the purpose of benefiting the inhabitants of all planets. Narada Muni travels all over the universe for the sole purpose of performing the best welfare activity for the entire universe by teaching everyone how to become a devotee of the Supreme Personality of Godhead. Thus Dhruva Maharaja felt fully assured that Narada Muni could fulfill his desire, even though the desire was very extraordinary.
The example of the sun is very significant. The sun is so kind that he distributes his sunshine everywhere, without consideration. Dhruva Maharaja requested Narada Muni to be merciful to him. He pointed out that Narada travels all over the universe just for the purpose of doing good to all conditioned souls. He requested that Narada Muni show his mercy by awarding him the benefit of his particular desire. Dhruva Maharaja was strongly determined to fulfill his desire, and it was for that purpose that he had left his home and palace.