Srimad-Bhagavatam: Canto 11 - Chapter 1 - Verse 16
Sanskrit:
श्रीभगवानुवाचपुत्रा हिरण्यगर्भस्य मानसा: सनकादय: ।पप्रच्छु: पितरं सूक्ष्मां योगस्यैकान्तिकीं गतिम् ॥ १६ ॥
ITRANS:
śrī-bhagavān uvācaputrā hiraṇyagarbhasyamānasāḥ sanakādayaḥpapracchuḥ pitaraṁ sūkṣmāṁyogasyaikāntikīṁ gatim
Translation:
The Supreme Personality of Godhead said: Once, the mental sons of Lord Brahmā, namely, the sages headed by Sanaka, inquired from their father about the difficult subject matter of the supreme goal of yoga.