CC Ādi 7.93
bhāgavatera sāra ei — bale vāre vāre
“Saying this, My spiritual master taught Me a verse from Śrīmad-Bhāgavatam. It is the essence of all the Bhāgavatam’s instructions; therefore he recited this verse again and again.
This verse from Śrīmad-Bhāgavatam (11.2.40) was spoken by Śrī Nārada Muni to Vasudeva to teach him about bhāgavata-dharma. Vasudeva had already achieved the result of bhāgavata-dharma because Lord Kṛṣṇa appeared in his house as his son, yet in order to teach others, he desired to hear from Śrī Nārada Muni to be enlightened in the process of bhāgavata-dharma. This is the humbleness of a great devotee.