SB 4.31.8
maitreya uvaca
iti pracetasam prsto
bhagavan narado munih
bhagavaty uttama-sloka
avistatmabravin nrpan
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
The great sage Maitreya continued: My dear Vidura, being thus petitioned by the Pracetas, the supreme devotee Narada, who is always absorbed in thoughts of the Supreme Personality of Godhead, began to reply.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
In this verse bhagavan naradah indicates that Narada is always absorbed in thoughts of the Supreme Personality of Godhead (bhagavaty uttama-sloka avistatma). Narada has no other business than thinking of Krsna, talking of Krsna and preaching about Krsna; therefore he is sometimes called bhagavan. Bhagavan means “one who possesses all opulences.” When a person possesses Bhagavan within his heart, he is also sometimes called bhagavan. Srila Visvanatha Cakravarti Thakura said, saksad-dharitvena samasta-sastraih: in every sastra the spiritual master is accepted directly as the Supreme Personality of Godhead. This does not mean that the spiritual master or a saintly person like Narada has actually become the Supreme Personality of Godhead, but he is accepted in this way because he possesses the Supreme Personality of Godhead within his heart constantly. As described here (avistatma), when one is simply absorbed in the thought of Krsna, one is also called bhagavan. Bhagavan possesses all opulence. If one possesses Bhagavan within his heart always, does he not automatically possess all opulence also? In that sense a great devotee like Narada can be called bhagavan. However, we cannot tolerate when a rascal or imposter is called bhagavan. One must possess either all opulences or the Supreme Personality of Godhead, Bhagavan, who possesses all opulences.