Śrīmad-Bhāgavatam · Text 3.6.38
Who is speaking and story frame
आत्मनोऽवसितो वत्स महिमा कविनादिना ।
संवत्सरसहस्रान्ते धिया योगविपक्कया ॥ ३८ ॥
ātmano ’vasito vatsa
mahimā kavinādinā
saṁvatsara-sahasrānte
dhiyā yoga-vipakkayā
O my son, the original poet, Brahmā, after mature meditation for one thousand celestial years, could know only that the glories of the Supreme Soul are inconceivable.
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