श्रीभगवानुवाच स्वायम्भुव ब्रह्मसत्रं जनलोकेऽभवत् पुरा । तत्रस्थानां मानसानां मुनीनामूर्ध्वरेतसाम् ॥ ९ ॥
śrī-bhagavān uvāca svāyambhuva brahma-satraṁ jana-loke ’bhavat purā tatra-sthānāṁ mānasānāṁ munīnām ūrdhva-retasām
The Supreme Lord said: O son of self-born Brahmā, long ago on Janaloka there was a great brahma-satra. Present there were sages, the mind-born sons of Brahmā, all perfect celibates (ūrdhva-retas).
Śrīla Śrīdhara Svāmī explains that the word satram here refers to a Vedic sacrifice in which all the participants are equally qualified to serve as priests. In this instance, each of the sages present in Janaloka could speak equally well on the topic of Brahman.
This verse states that long ago a great sacrificial session (brahma-satra) of the self-born Brahmā took place in Janaloka, attended by exalted sages.
They are sages born from Brahmā’s mind—highly purified ascetics present at Brahmā’s sacrificial assembly in Janaloka.
It points to disciplined conservation and elevation of one’s life-energy through purity and self-control, supporting deep spiritual focus and devotion.