SB 12.9.7

sūta uvāca
itīḍito ’rcitaḥ kāmam
 ṛṣiṇā bhagavān mune
tatheti sa smayan prāgād
 badary-āśramam īśvaraḥ
Synonyms: 
sūtaḥ uvāca — Sūta Gosvāmī said; iti — in these words; īḍitaḥ — glorified; arcitaḥ — worshiped; kāmam — satisfactorily; ṛṣiṇā — by the sage Mārkaṇḍeya; bhagavān — the Personality of Godhead; mune — O wise Śaunaka; tathā iti — “so be it”; saḥ — He; smayan — smiling; prāgāt — departed; badarī-āśramam — for the hermitage Badarikāśrama; īśvaraḥ — the Supreme Lord.
Translation: 
Sūta Gosvāmī said: O wise Śaunaka, thus satisfied by Mārkaṇḍeya’s praise and worship, the Supreme Personality of Godhead, smiling, replied, “So be it,” and then departed for His hermitage at Badarikāśrama.
Purport: 

The words bhagavān and īśvara in this verse refer to the Supreme Lord in His incarnation as the twin sages Nara and Nārāyaṇa. According to Śrīla Viśvanātha Cakravartī Ṭhākura, the Supreme Lord smiled ruefully, because He prefers that His pure devotees stay away from His illusory energy. Curiosity to see the illusory energy of the Lord sometimes develops into sinful material desire. Nonetheless, to please His devotee Mārkaṇḍeya, the Lord granted his request, just as a father who cannot convince his son to give up pursuing a harmful desire may let him experience some painful reaction so that he will then voluntarily desist. Thus, understanding what would soon happen to Mārkaṇḍeya, the Lord smiled as He prepared to display the illusory potency to him.